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Version 16.0 April 3, 2007

HST Phase II Proposal Instructions for Cycle 16

Operations and Data Management Division 3700 San Martin Drive Baltimore, Maryland 21218 help@stsci.edu

Operated by the Association of Universities for Research in Astronomy, Inc., for the National Aeronautics and Space Administration


Revision History
Version 16.0 Type GO Date April 2007 Editor Jim Younger Initial release for Cycle 16

Version 16.0 is issued in coordination with the APT release and is intended to be fully compliant with Cycle 16 APT. Shelf life: This version should not be used after September 1, 2007 without checking for a more recent version

This is the General Observer version. If you would like some hints on how to read and use the PDF document, click on: Some Pointers in PDF and APT JavaHelp

How to get help
1. Visit STScI's Web site: http://www.stsci.edu/

where you will find resources for observing with HST and working with HST data.
2. Contact your Program Coordinator (PC) or Contact Scientist (CS) you have

been assigned. These individuals were identified in the notification letter from STScI.
3. Send e-mail to help@stsci.edu, or call 1-800-544-8125.

From outside the United States, call 1-410-338-1082.


Table of Contents
HST Phase II Proposal Instructions for Cycle 16
Part I: Phase II Proposal Writing
1.1 1.2 1.3 1.4 1.5 1.6
................................. 1 .................... 3 4 4 4 5 5 6

Chapter 1: About This Document

Document Design and Structure ............................... Changes Since the Previous Version ....................... Document Presentation ............................................... Technical Content ......................................................... Where to Find Additional Information ....................... Some Pointers in PDF and APT JavaHelp .............

Chapter 2: The Basics of Phase II Proposals............................................................................................ 9
2.1 How to Prepare and Submit Phase II Information ......................................................................... 9
2.1.1 Astronomer's Proposal Tool (APT) ............................. 9 2.1.2 Entering Information: The APT Graphical User Interface (GUI) versus the Text Proposal File .............................. 10 2.1.3 APT Tools ................................................................. 11 2.1.4 Submitting Your Program ......................................... 12 2.2 What to Submit ............................................................ 12 2.3 General Instructions ................................................... 13 2.3.1 Proposal Information [Proposal_Information] ........... 13 2.3.2 Proposal Description................................................. 15 2.3.3 Investigators ............................................................. 16 2.3.4 Target Information [Fixed_Targets,
iii


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Solar_System_Targets, Generic_Targets] .................... 2.3.5 Visit Information [Visits] ............................................ 2.4 Examples and General Advice................................. 2.4.1 Acquisitions and Pointings ........................................ 2.4.2 Examples .................................................................. 2.4.3 Common Problems ................................................... 2.4.4 Consideration of Limited Resources ......................... 2.5 Text Proposal File ...................................................... 2.5.1 Basic Syntax Rules ................................................... 2.5.2 Sample Text Proposal File Template........................

17 17 17 17 18 19 19 21 21 21

Chapter 3: Fixed and Generic Targets

....... 25

3.1 Target Number [Target_Number] .......................... 27 3.2 Target Name [Target_Name and Alternate_Names] ........................................................ 27
3.2.1 3.2.2 3.2.3 3.2.4 Catalog Name ........................................................... Uncataloged Targets ................................................ Common Names ....................................................... Special Targets ......................................................... 28 29 30 30

3.3 Target Category and Target Description [Description] .................................................................. 31 3.4 Target Position Type[Position] ............................... 36
3.4.1 Required Accuracies of Target Positions.................. 36 3.4.2 Equatorial Coordinates ............................................. 38 3.4.3 Positional Offsets ...................................................... 39 3.4.4 Region of Sky (Extended Targets)............................ 41 3.4.5 Determining Coordinates in the Guide Star Selection System (GSSS) Reference System .............................. 42 3.4.6 A Caution on Astrometry Prepared from STScI Plate Scans ............................................................................ 44 3.4.7 Early Acquisitions ..................................................... 45 3.5 Equinox for Coordinates [Equinox] ......................... 45

3.6 Coordinate Reference Frame [Reference_Frame]........................................................ 45 3.7 Radial Velocity or Redshift [RV_ or _Z] ................ 46 3.8 Is Proper Motion or Parallax Relevant? ................. 46
3.8.1 Proper Motion and Parallax Data.............................. 3.9 Flux Data [Flux and Other_Fluxes] ...................... 3.9.1 General Guidelines on What Flux Data to Include.... 3.10 Bright-Object Constraints ........................................ 46 47 48 51


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3.11 Comments [Comments] ......................................... 52 3.12 Generic Targets List [Generic_Targets] ............ 53
Target Number(s) [Target_Number] ....................... Target Name [Target_Name] .................................. Target Description [Description] ............................. Flux Data [Flux]....................................................... Comments [Comments] .......................................... Generic Target Specifications [Criteria} .................. 3.13 Getting Coordinates Coordinated ......................... 3.12.1 3.12.2 3.12.3 3.12.4 3.12.5 3.12.6 53 53 54 54 54 54 56

Chapter 4: Solar System Targets
4.1 4.2 4.3 4.4 Target Target Target Target

................... 59 61 62 64 65 67 69 75 75 76 76 81 82 84 84 85

Number [Target_Number] .......................... Name [Target_Name] .................................. Description [Description] ............................ Position .............................................................

4.4.1 Target Position Level 1 [Level_1] ............................. 4.4.2 Target Position Level 2 [Level_2] ............................. 4.4.3 Target Position Level 3 [Level_3] ............................. 4.5 Ephemeris Uncertainty [Ephem_Uncert] ............. 4.6 Acquisition Uncertainty [Acq_Uncert] ................... 4.7 Observing Windows [Windows] ............................. 4.7.1 Default Target Windows ........................................... 4.8 Flux Data [Flux and Other_Fluxes] ...................... 4.9 Comments [Comments] ........................................... 4.10 Illustrations of Orbital Longitude ............................ 4.11 Examples of Target List Blocks .............................

Chapter 5: Visits, Exposures and Exposure Groups .................................................................
5.1 Visit Number and Status .......................................... 5.2 Visit Priority [Visit_Priority] ........................................ 5.3 Visit-level Special Requirements [Visit_Requirements] .................................................. 5.4 On Hold Comments [On_Hold_Comments] ....... 5.5 Visit Comments [Visit_Comments] ....................... 5.6 Exposure Number [Exposure_Number] ..............

89 91 92 92 93 93 94


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5.7 Exposure Label [Exposure_Label] .......................... 94 5.8 Target Name [Target_Name] ................................... 94
5.8.1 Astronomical Targets ................................................ 5.8.2 Special Targets ......................................................... 5.9 Instrument Configuration [Config] .......................... 5.10 Operating Mode [Opmode].................................... 5.11 Aperture or Field of View [Aperture] ................... 5.12 Spectral Element [Sp_Element].......................... 95 95 95 96 96 96

5.13 Central Wavelength or Range if Grating or Prism Used [Wavelength] ....................................................... 97 5.14 Number of Times to Iterate the Exposure [Number_of_Iterations].............................................. 97 5.15 Time per Exposure [Time_Per_Exposure] ....... 98 5.16 Exposure-level Comments [Comments] ............ 99 5.17 Optional Parameters[Optional_Parameters] ...... 99 5.18 Exposure-level Special Requirements[Special_Requirements]................................. 99 5.19 Exposure Containers: Exposure Groups, Coordinated Parallels and Patterns ..................................... 100 5.20 Subexposures .......................................................... 101
5.20.1 Actual_Duration .................................................... 101 5.20.2 Orbit_Number ....................................................... 101

Chapter 6: Parallel Science Exposures

.. 103

6.1 Parallel Science Limitations .................................... 104 6.2 Pure Parallels ............................................................. 105 6.3 Coordinated Parallel Containers............................ 107
6.3.1 6.3.2 6.3.3 6.3.4 6.3.5 6.3.6 Instrument Configuration ........................................ Targets.................................................................... Special Requirements............................................. Optional Parameters ............................................... Ordering Restrictions and Interpretations ............... Efficiency Considerations ....................................... 108 108 109 110 111 111


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Chapter 7: Special Requirements [Visit and Exposure Special_Requirements] ...................................

113

7.1 Introduction to Special Requirements: Syntax and Rules ......................................................... 114 7.2 Visit-level Special Requirements ........................... 117
Guiding ................................................................... Target Orientation ................................................... Special Observation Requirements ........................ Timing Requirements.............................................. Conditional Requirements ...................................... 7.3 Exposure-level Special Requirements ................. 7.3.1 Target Acquisition ................................................... 7.3.2 Target Position........................................................ 7.3.3 Special Observation Requirements ........................ 7.3.4 Special Communications Requirements ................. 7.3.5 Timing Requirements.............................................. 7.2.1 7.2.2 7.2.3 7.2.4 7.2.5 117 120 130 131 134 135 135 136 138 139 141

Chapter 8: Pointings and Patterns

.............. 145

8.1 Pointing the Telescope ............................................ 145 8.2 Introduction to Patterns............................................ 145
8.2.1 APT User Interface ................................................. 8.2.2 Text Proposal File ................................................... 8.3 How to Fill Out the Pattern Parameters Form .... 8.3.1 Pattern Parameters................................................. 8.4 Convenience Patterns .............................................. 8.4.1 WFPC2 Patterns ..................................................... 8.4.2 ACS Patterns (HRC and WFC unavailable for Cycle 16) ...................... 8.4.3 NICMOS Patterns ................................................... 146 147 148 149 152 153 155 160

Part II: Supported Science Instruments

............ 169

Chapter 9: Wide Field Planetary Camera 2 (WFPC2) ......................................................................... 171
9.1 Introduction to WFPC2............................................. 172 9.2 Mode = IMAGE


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Config = WFPC2 .......................................................... 173
Aperture or FOV ..................................................... Spectral Elements................................................... Wavelength ............................................................. Optional Parameters ............................................... Number of Iterations ............................................... Time Per Exposure ................................................. 9.3 Tabular Reference Data .......................................... 9.4 WFPC2 Aperture Coordinate System .................. 9.2.1 9.2.2 9.2.3 9.2.4 9.2.5 9.2.6 174 175 175 176 177 177 178 182

Chapter 10: Fine Guidance Sensors (FGS) ................................................................................

183

10.1 Introduction to the FGS ......................................... 184 10.2 Mode = POS Config = FGS ................................................................ 185
10.2.1 10.2.2 10.2.3 10.2.4 10.2.5 Aperture or FOV ................................................... Spectral Element .................................................. Optional Parameters ............................................. Special Requirements........................................... Time Per Exposure ............................................... 185 186 186 187 188

10.3 Mode = TRANS Config = FGS ................................................................ 188
Aperture or FOV ................................................... Spectral Element .................................................. Optional Parameters ............................................. Time Per Exposure ............................................... Special Requirements........................................... 10.4 Tables and Illustrations ......................................... 10.3.1 10.3.2 10.3.3 10.3.4 10.3.5 188 188 189 189 189 190

Chapter 11: Advanced Camera for Surveys (ACS) .................................................

193

11.1 Introduction to the ACS ......................................... 194 11.2 Mode = ACCUM Config = ACS/WFC(Unavailable for Cycle 16) ........ 195
11.2.1 11.2.2 11.2.3 11.2.4 Aperture or FOV ................................................... Spectral Element .................................................. Wavelength ........................................................... Optional Parameters ............................................. 196 196 197 197


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11.2.5 Number of Iterations ............................................. 198 11.2.6 Time Per Exposure ............................................... 198

11.3 Mode = ACCUM Config = ACS/HRC (Unavailable for Cycle 16) ....... 198
11.3.1 11.3.2 11.3.3 11.3.4 11.3.5 11.3.6 Aperture or FOV ................................................... Spectral Element .................................................. Wavelength ........................................................... Optional Parameters ............................................. Number of Iterations ............................................. Time Per Exposure ............................................... 199 199 200 200 201 201

11.4 Mode = ACQ Config = ACS/HRC (Unavailable for Cycle 16) ....... 203
11.4.1 11.4.2 11.4.3 11.4.4 11.4.5 11.4.6 Aperture or FOV ................................................... Spectral Element .................................................. Wavelength ........................................................... Optional Parameters ............................................. Number of Iterations ............................................. Time Per Exposure ............................................... 203 203 203 203 204 204

11.5 Mode = ACCUM Config = ACS/SBC ...................................................... 204
Aperture or FOV ................................................... 204 Spectral Element .................................................. 204 Wavelength ........................................................... 204 Optional Parameters ............................................. 205 Number of Iterations ............................................. 205 Time Per Exposure ............................................... 205 11.6 Tabular Reference Data ........................................ 205 11.6.1 Spectral Elements for WFC and HRC .................. 205 11.6.2 Ramp Filter Wavelength Ranges .......................... 209 11.6.3 Spectral Elements for ACS/SBC........................... 209 11.6.4 Allowed Combinations of Aperture, Spectral Element & Readout ................................................................... 210 11.7 ACS Aperture Coordinate System ...................... 211 11.5.1 11.5.2 11.5.3 11.5.4 11.5.5 11.5.6

Chapter 12: Near Infrared Camera and Multi-Object Spectrometer (NICMOS) ......................................................................

213

12.1 Introduction to NICMOS ........................................ 214 12.2 Mode = ACCUM


x

Config = NIC1 or NIC2 or NIC3 ................................ 215
12.2.1 12.2.2 12.2.3 12.2.4 12.2.5 12.2.6 12.2.7 Aperture or FOV ................................................... Spectral Elements................................................. Wavelength ........................................................... Optional Parameters ............................................. Number of Iterations ............................................. Time Per Exposure ............................................... Special Requirements........................................... 216 216 216 216 217 217 218

12.3 Mode = MULTIACCUM Config = NIC1 or NIC2 or NIC3 ................................ 218
12.3.1 12.3.2 12.3.3 12.3.4 12.3.5 12.3.6 12.3.7 Aperture or FOV ................................................... Spectral Elements................................................. Wavelength ........................................................... Optional Parameters ............................................. Number of Iterations ............................................. Time Per Exposure ............................................... Special Requirements........................................... 218 218 218 218 220 220 220

12.4 Mode = ACQ Config = NIC2 ............................................................... 223
Aperture or FOV ................................................... Spectral Elements................................................. Wavelength ........................................................... Optional Parameters ............................................. Number of Iterations ............................................. Time Per Exposure ............................................... Special Requirements........................................... 12.5 Tabular Data ............................................................ 12.5.1 TPG_TIME Values ................................................ 12.5.2 NICMOS Apertures ............................................... 12.5.3 NICMOS Spectral Elements ................................. 12.6 Illustrations ............................................................... 12.4.1 12.4.2 12.4.3 12.4.4 12.4.5 12.4.6 12.4.7 223 223 223 223 223 223 224 224 224 225 226 229

Index

...................................................................................... 235


PART I:

Phase II Proposal Writing
The chapters in this section explain how to use the Phase II Instructions, how to fill out your Phase II information file and submit it to STScI. It also explains where to go for help and describes the information that must be submitted to STScI by GOs and GTOs during Phase II. Chapter 1: About This Document / 3 Chapter 2: The Basics of Phase II Proposals / 9 Chapter 3: Fixed and Generic Targets / 25 Chapter 4: Solar System Targets / 59 Chapter 5: Visits, Exposures and Exposure Groups / 89 Chapter 6: Parallel Science Exposures / 103 Chapter 7: Special Requirements Special_Requirements] / 113 Chapter 8: Pointings and Patterns / 145 [Visit and Exposure

1


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CHAPTER 1:

About This Document
In this chapter. . .
1.1 Document Design and Structure 1.2 Changes Since the Previous Version 1.3 Document Presentation 1.4 Technical Content 1.5 Where to Find Additional Information 1.6 Some Pointers in PDF and APT JavaHelp / / / / / / 4 4 4 5 5 6

Proposals to observe with Hubble Space Telescope (HST) are reviewed in two phases managed by the Space Telescope Science Institute (STScI). In Phase I, proposers submitted an Observation Summary for review by the Telescope Allocation Committee (TAC). The Observation Summary provides only general descriptions of the targets and of the proposed observations. The TAC review results in a list of accepted proposals. During Phase II, General Observers (GOs) with accepted proposals, as well as Guaranteed Time Observers (GTOs), must provide complete details of their proposed observations so that STScI can conduct a full technical feasibility review. The Phase II information will then be used to schedule the actual observations and obtain data. This document, the Phase II Proposal Instructions, has the following purposes: · To describe the information that must be submitted to STScI by GOs and GTOs during Phase II. · To describe what you have to provide in APT (Astronomer's Proposal Tool). · To show how to submit the information to STScI. Readers of this document should be familiar with the Cycle 16 Call for Proposals, issued in October 2006, and with the Instrument Handbooks.

3


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Chapter 1: About This Document

Note on colors in the GO Version: Blue text shows active external references and cross-references to other parts of this document. Brown text pertains to use of the Text Proposal File.

1.1 Document Design and Structure
These Instructions are meant to be read on-line, although many readers may wish to print selected portions. Many cross-references have been added to make navigation easy and convenient. A comprehensive table of contents allows you to go directly to chapters, sections and subsections. Each chapter starts with a listing of sections and subsections, each linked to its page. Near the beginning of most chapters, a list of figures and tables is provided; this list is cross-referenced for convenient navigation to a particular item you may wish to examine. Also, an index has been provided.

1.2 Changes Since the Previous Version
Initial Release for Cycle 16. Significant changes include: · ACS HRC and WFC are not available · A new proposal type, GO/SURVEY has been added

1.3 Document Presentation
Navigation Cross-references and external references highlighted in blue can be accessed by clicking on the item. Text Proposal File Instructions Sections and text in brown have been added for those proposers who elect to export, and then edit their proposal in a Text Proposal File. For


Technical Content

5

guidelines on when you might use this template, see "Using the Text Proposal File" in Chapter 2. Available Formats Proposers can access this information in two formats: PDF via the Web and Sun JavaHelp via the Astronomer's Proposal Tool (APT). · The PDF version available on the Web will be the only one that you can be certain is up-to-date. It can be downloaded and printed if you wish, and when used on-line provides "instant" access to internal and external cross-references. · The JavaHelp version available in APT should not be printed due to the limitations of printing in Java. You can use the internal cross-references, but the external references in JavaHelp have been disabled. Reader Feedback We have striven to present this critical, detailed, and complex information in a form that allows it to be used accurately and effectively. Your comments on its good and bad qualities will help us in the future; send e-mail to help@stsci.edu.

1.4 Technical Content
Available Science NICMOS, WFPC2 and the side 2 electronics in Cycle 16 (see ACS Web Instruments for Cycle 16 FGS are available in Cycle 16. Due to a failure in January 2007 , only the ACS SBC is available for Site).

Instrument Modes, Special Requirements, etc. Some changes have been made to these Instructions since the previous version to correct errors and omissions, and to document new modes or options. There are too many to list, but as long as you use the most recent version the information provided should reflect our current state of knowledge.

1.5 Where to Find Additional Information
As you write your Phase II proposal, you will probably need to consult the Instrument Handbooks for additional information on one or more Science Instruments. These handbooks are available on the Web in both PDF and


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Chapter 1: About This Document

HTML versions at http://www.stsci.edu/hst/HST_overview/documents There are some policies that were delineated in the Call for Proposals, which asked for Phase I proposals. You may wish to review those, particularly the sections discussing limited resources.

1.6 Some Pointers in PDF and APT JavaHelp
PDF Online and Print Adobe's Portable Document Format (PDF) is the standard for the commercial sector because it is easily produced with modern documentation software and has many excellent features. If you're new to PDF here are some hints that you may find useful: · PDF has links, just like HTML. Anything in blue in this document is a link you can click on to go somewhere else. · PDF can print selected pages. Note that the page numbers you enter are PDF's sequential numbers (look at the bottom of the Acrobat window to see where you are). · PDF is searchable with most viewing software such as Adobe's Reader and Apple's Preview. · You can move up or down page by page using the scroll bar on the right of your Acrobat window; just click above or under the indicator that shows your relative position. You can also click and hold on this indicator to speed through the document. · If you wish to save this document as a PDF file on your local machine, click with your right mouse button on the Institute's Web page that has the Phase II information at the spot where you link to the PDF file. In other words, your left button opens the file in Acrobat, but the right button lets you save the file if you pull down to "Save Link as." · Look at Acrobat's help facility (the help button is in the upper right corner of the Acrobat window) for more pointers. APT JavaHelp The Astronomer's Proposal Tool (APT) user interface provides access to this document via Sun JavaHelp -- a help format specifically designed for Java-based applications. · The internal cross-references are linked (in blue), but all external references have been disabled.


Some Pointers in PDF and APT JavaHelp

7

· The JavaHelp viewer provides access to a table of contents and an index; all the listed items are linked to the referenced sections. Once you are in a document, you can use the table of contents, the index, or the cross-references in the text to navigate to other parts of the document as you would in html. · JavaHelp has a very useful search utility. · Some of the sections in the Phase II Instructions are used for "context-sensitive" help in APT. At the top of the APT user interface, click on the "Help" menu item for access to this document and instructions on how to use the context-sensitive help. We welcome your comments and thoughts for improving how we provide information to you.


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Chapter 1: About This Document


CHAPTER 2:

The Basics of Phase II Proposals
In this chapter . . .
2.1 How to Prepare and Submit Phase II Information 2.2 What to Submit / 2.3 General Instructions / 2.4 Examples and General Advice / 2.5 Text Proposal File / /9 12 13 17 21

2.1 How to Prepare and Submit Phase II Information
The computer software used to schedule and execute HST observations can interpret the proposal information only if it is in the proper format. Therefore, proposals must be filled out accurately, completely, and in strict accordance with the instructions in this document. Observers now have the capability and responsibility, with the help of their Program Coordinator (PC) and/or Contact Scientist (CS) for creating and submitting proposals that are not only syntactically correct but also feasible and schedulable. The Astronomer's Proposal Tool (APT) will help you achieve this.

2.1.1 Astronomer's Proposal Tool (APT)
With APT you can prepare your Phase II program on your computer and then submit it electronically to STScI. You will use a copy of your Phase I proposal (marked up in XML), which contains all the information from your Phase I submission. If you haven't done so already, please consult the APT Web Page for detailed instructions on how to install and use APT on

9


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Chapter 2: The Basics of Phase II Proposals

your computer. Observers without access to a suitable computer platform to run APT for Phase II should contact their PC.

2.1.2 Entering Information: The APT Graphical User Interface (GUI) versus the Text Proposal File
In the previous proposal entry system, RPS2, you could enter and edit information as text (usually in the form =) using a template and your favorite text editor. Also, you could use the Proposal Editor (PED), a graphical editor in RPS2 designed for editing your Phase II program. In APT you can enter proposal information by using either the APT Form/Spreadsheet Editors via a GUI or a Text Proposal File that employs a "simplified" RPS2 syntax. This text file has been developed for APT as an alternative method for editing proposals outside of the APT GUI; you use a flat ASCII file format that is similar to the RPS2 .prop file that was used in HST cycles 5-11. Small changes to the original RPS2 format were necessary to accommodate enhancements that came with APT, and some of the syntax has been made stricter in order to make reading of the file more robust. You create this file in APT by exporting your proposal into a text proposal file format (for details please see the APT Web Page). Using the APT GUI In most of the fields in the APT graphical interface, you choose a keyword or parameter in a list from a pull-down menu, or check a box. In a few other fields (e.g., Other Fluxes, Observing Windows and Criteria in the Targets forms) you enter free text in the field using the formats specified in this document. Required items are marked with a red "x" if you haven't selected or entered a . Also, for many of the keywords, a tooltips message will appear when you place your pointer on the keyword: area. Using the Text Proposal File When creating or editing large repetitive proposals, editing with APT's graphical interface can be inefficient and prone to error. We present two examples where you may want to use a text proposal file.
1. You are building a large repetitive program with many targets and

visits in order to create a mosaic. Initially, you would use APT to build a proposal that has one or two targets and one of each of the unique visits. You would then run the Orbit Planner and Visit Planner to make sure that the visits fill the right number of orbits and schedule. Then, you would export this small template proposal to the Text Proposal File format, and use scripts or your favorite editor to build your program into a larger version. You would then import the resulting file back into APT for checking and processing.


How to Prepare and Submit Phase II Information

11

2. You have already built a fairly large program in APT by creating

unique exposures and visits, and then used the duplicate and multiple duplicate features in APT. Then, you discover that you need to make a small change to a large number of exposures (such as removing or adding an optional parameter). This would be tedious to do in the APT GUI, but straightforward in the Text Proposal File. Simply export your program to the Text Proposal File format, make your changes in an editor, and then import the Text Proposal File back into APT for new processing. Table 2.1 summarizes some of the differences between the APT GUI and the Text Proposal File.
Table 2.1: Comparison of APT GUI and the Text Proposal File
Data Entry Method APT Use the Form or Spreadsheet Editors via the APT User Interface Syntax For most of the fields (exceptions noted below1), choose a keyword from a pull-down list, or check a checkbox, or enter a text in the field provided. Enter free text in the file in the form =. You must conform to the proper syntax described in this document. Help Features and Error Checking 1) Required data marked with a red x 2) Tooltips (e.g., a message noting a required item and its format) provided during data entry 3) Context-sensitive help available None while editing. After editing your proposal, you must import it back into APT (see the APT Web page for instructions). Once you have imported your program back into APT you can run the diagnostics tool.

Text Proposal File

After exporting your proposal from APT to the text file, edit it using your favorite editor.

1. The exceptions are: - Other Fluxes field for all types of Targets - Criteria field for Generic Targets In these fields you must enter text (, and any separators) exactly as described in the relevant sections of this document.

2.1.3 APT Tools
APT also provides tools to help you plan your observations, such as an Aladin based visualization tool, an Orbit Planner and a Visit Planner (see the Using APT web page). If you have any problems using APT, or have any questions about your proposal, please feel free to contact your assigned Program Coordinator (PC) and/or Contact Scientist (CS). Programs without an assigned CS may also contact help@stsci.edu for help with APT.


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Chapter 2: The Basics of Phase II Proposals

2.1.4 Submitting Your Program
After you submit your Phase II program, the APT system will give you an automatic electronic acknowledgment. This should be followed in a few days by an acknowledgment from your PC. If, at the time of submission, the proposal contains errors, the APT submission system will give a warning, but will allow the proposal to be submitted. However, the proposal will be flagged, and your PC will contact you within a few days to discuss how to proceed.

The resolution of errors in the Phase II Program is the responsibility of the Principal Investigator. The fact that APT may allow you to submit a program that contains errors does not mean that your program can or will be scheduled. We strive to make APT a useful aid for preparing and checking your Phase II program, but it is nevertheless imperfect. On rare occasions syntax errors are not detected. Also, APT does not check for guide stars.

2.2 What to Submit
Observers must submit their Phase II proposal to STScI by the Phase II deadline. It should contain the following: · Updated Proposal Information: This section includes the title, the abstract, a Phase II ID, a proposal description, PI and CoI information. Please note that some general information is very useful for a thorough and helpful technical review of your proposal. You may wish to include parts of your Phase I science discussion, but please note that all the Phase II information you provide will be freely available via the Web. · Target Information: The information for one or more of the Fixed, Solar System, or Generic Targets must be completed. If necessary, proper motion and parallax information should be supplied for fixed targets. Detailed instructions for filling out the target data, as well as the proper motion and parallax information, are provided in Chapter 3: Fixed and Generic Targets on page 25 and Chapter 4: Solar System Targets on page 59 of this document.


General Instructions

13

· Visit, Exposure Group, and Exposure Specifications: These specifications include orientation information, scheduling requirements, SI information, exposure special requirements and so on. Required items will be clearly noted as you complete the specifications. General instructions for completing this section are provided in Chapter 5: Visits, Exposures and Exposure Groups on page 89 of this document.

2.3 General Instructions
When you first bring up APT, you will have to convert the information in your Phase I proposal, which is an XML file, into a Phase II program format using the "Phase I->Phase II" conversion button on the APT User Interface. Note the following general instructions and conventions when entering your Phase II information: · After converting your Phase I Proposal into Phase II information, please verify that all the general information is correct and readable. · Entries in text must precisely conform to the formats specified in this document. If you have decided to use the Text Proposal File, the order of the entries must be correct as well (see Section 2.5 on page 21). · Proposal data text may contain only standard ASCII characters. All other symbols must be spelled out. Greek letters must be spelled out (e.g. BETA-LYR, H-ALPHA). The degree sign should be replaced with "D" (e.g. BD+16D516). Subscripts and superscripts are not allowed. · Additional information not covered by the keywords and values already provided may be entered in the "Additional Comments" or "Comments" boxes. · When providing a Target "Description" please use the target keywords and syntax presented in Tables 3.2 to 3.10 and Table 4.2. If you are unable to use the APT software, please contact your PC (listed in your notification letter) to make other arrangements.

2.3.1 Proposal Information [Proposal_Information]
This block contains basic information about the proposal including the Title, Abstract, Category, and Cycle. After converting your proposal from


14

Chapter 2: The Basics of Phase II Proposals

Phase I to Phase II, your Phase II program will have the program information filled out based on your Phase I submission. Proposal Title Abstract The Abstract from your Phase I submission has been included in your Phase II information. Please check this since you may need to update this text based on your final TAC allocation. If a Phase II submission is not based on a Phase I proposal, please fill in missing information. Phase II ID This ID will be provided to you by your Program Coordinator. STScI Edit Number This field holds a counter for an operational version number of the proposal and cannot be edited by the user. If you are connected to the internet, the version number in your proposal file is compared to the one in the STScI proposal database when a proposal is opened or submitted. In either case, if your file's version number is less than the database's number for that proposal, you will get a pop up warning that a more recent version is available (via APT's Retrieve from STScI). This prevents you from doing an update with an old copy of the proposal, or making edits to a version that does not include changes your PC has made to the proposal.The STScI software increments this number whenever the Phase II file is edited by STScI staff. Proposal Cycle Unless you have been told otherwise, the Cycle should be 16. Multiple values of Cycle are not permitted. Proposal Category For those Phase II submissions that are not based on a Phase I proposal, the Category should be selected from one of the following:
GO (General Observer) GO/DD (Director's Discretionary time)

GO/SURVEY (GO Survey Programs) SNAP (snapshot proposals) GTO (Guaranteed Time Observer)

A Category of SNAP is used for "snapshot" programs. By their nature these programs take advantage of otherwise-unused blocks of telescope


General Instructions

15

time for relatively short exposures. SNAP exposures therefore must carry as few restrictions as possible. In particular, Special Requirements should not ordinarily be used with SNAP programs (consult with your Program Coordinator if you feel you need to do so). Some special policies apply to SNAP programs: in particular, STScI will not repeat failed SNAP exposures. Starting with Cycle 16 a GO/SURVEY Category has been created as an alternative option for programs that are statistical in nature. These proposals are like SNAP programs in that they have a large pool of candidate targets from which a subset will be observed. As in all GO programs, GO/SURVEY programs have been assigned a specific number of orbits, but specific targets are not guarenteed to be observed. These observations cannot require special scheduling constraints (for example, CVZ, any timing requirement, or any telescope orientation requirements) and are limited to durations of no more than 48 minutes per orbit. For pure parallel proposals (see 6.2 Pure Parallels on page 105), check the "Parallel" checkbox next to the Proposal Category in the Proposal Information form. Please note that SNAP/PAR and GO/SURVEY/PAR are not valid proposal types. Availability You must choose supported. If the observing modes normally offered by STScI to GOs do not meet the needs of your program, please contact your Program Coordinator. Parallel Pointing Tolerance This information is required with pure parallel proposals. The Parallel_Pointing_Tolerance gives the maximum acceptable variation in pointing at the parallel aperture during a parallel visit. The units are arcsec but must be explicitly stated. The number must be non-negative (e.g., 10). This will normally be set to the maximum pointing change that still allows exposures taken at slightly different pointings to be combined later during data analysis.

2.3.2 Proposal Description
Proposal Text Sections These four sections are needed for STScI to execute your program properly. Not all questions will need to be answered by every observer, and note that the answers to these questions will be made public. As with the Abstract, please review this text to make certain the information is correct.


16

Chapter 2: The Basics of Phase II Proposals

Description of Obser vations [Observing_Description] Provide a detailed description of your observing plans. Text from your Phase I proposal has been inserted, but it will need updating based on your final TAC allocation and on details worked out in Phase II. Justification of Real-time observations and Special Scheduling Requirements [Realtime_Justification] Provide an explanation for any real-time or special scheduling requirements, if they have been requested. Information from your Phase I proposal has been inserted, but it is possible that the text will need updating based on your final TAC allocation, to include the details worked out in Phase II, and to remove any special calibration requirements (see below). Justification of Special Calibration Requirements [Calibration_Justification] Provide a justification for any special calibrations required for your program, if requested. Additional Comments [Additional_Comments] Provide any additional comments that you feel STScI needs to know in order to properly implement your program.

2.3.3 Investigators
These sections contain the names of the Principal Investigator (PI), all Co-Investigators1 (CoI), and their institute affiliations. This information comes from your Phase I proposal submission. If one of the Co-Investigators (or another individual) is to serve as the contact for a program, then the Contact keyword box should be checked. The Contact is the person the Principal Investigator has designated to receive all (non-budgetary) questions/information on the program and to be the official voice for the team. Only one person may be designated as the Contact. Once designated, only the Contact may make Change Requests so that conflicting requests are not made. If any of the Investigators have changed addresses between the Phase I and Phase II submissions (or any time after the Phase I submission), please contact your Program Coordinator with the updated address. You cannot use the Phase II submission to implement address changes. For Phase II submissions that are not based on a Phase I proposal, please fill in the information accordingly.

1. The number of CoIs is limited to 99.


Examples and General Advice

17

2.3.4 Target Information [Fixed_Targets, Solar_System_Targets, Generic_Targets]
Chapter 3: Fixed and Generic Targets on page 25 and Chapter 4: Solar System Targets on page 59 describe how to fill out the Target Lists.

2.3.5 Visit Information [Visits]
Chapter 5: Visits, Exposures and Exposure Groups on page 89 of this document describes how to fill out the Visit and Exposure Specifications. Instructions for submitting parallel observations are given in Chapter 6: Parallel Science Exposures on page 103, and the detailed, instrument-specific parameters are described in Part II: Supported Science Instruments on page 169.

2.4 Examples and General Advice
2.4.1 Acquisitions and Pointings
Getting HST located and oriented properly lies at the heart of successful observations, especially when a small aperture is being used, and there are a number of ways to do that. The remarks here apply specifically to fixed targets, and mostly apply to the use of small apertures, although many of them can be applied to moving targets as well. For more information, see Section 3.4 on page 36. First, you have to acquire an object successfully that is at or near the position at which the science observation will be made. The object to be acquired should meet these conditions:
1. It should be a point source or nearly enough to point-like that the cen-

tering algorithms can determine a precise centroid.
2. The object's coordinates must be both precise and accurate and any

proper motion must be known. This requirement boils down to the need for the object to fall within the search region at the time of the acquisition. For this to happen the coordinates must also be consistent with the Guide Star Catalog or they must fall within another system that can be related to the GSC. This is why the source of the acquired object's coordinates are required.
3. The object must be neither too bright nor too faint for the instrument

mode used. These conditions are described in the various Instrument Handbooks. The coordinates for the acquired object can be specified in several ways:


18

Chapter 2: The Basics of Phase II Proposals

· As explicit absolute celestial coordinates, i.e., RA and DEC. See Section 3.4.2 on page 38. · As celestial coordinates relative to another nearby object, using offsets in RA and DEC. See Section 3.4.3 on page 39. · As a REGION; see Section 3.4.4 on page 41. Second, once the acquisition has been made, the telescope must be repositioned to the precise point desired. This step is unnecessary, of course, if the object acquired in the first instance is the object to be observed. Repositioning can be implicit or explicit. An offset is implicit when a target such as "XX-OFFSET" is acquired with some ACQ mode, and then "XX" is observed via a science exposure. This often leads to confusion because no specific motion of the telescope has been provided, but that motion is implied by specifying the separate targets with different coordinates. "XX-OFFSET" is specified for the acquisition because it is bright enough and point-like enough to be acquired successfully, but the coordinates specified by "XX" are what is to be observed. An offset is explicit when you use a Special Requirement such as POS TARG (see POSition TARGet ,) to move the telescope away from the position acquired. In this scheme, the position specified in the acquisition is placed at the fiducial point for the aperture requested (in general the geometric center of the aperture). The POS TARG then moves the telescope relative to that nominal position. Thus POS TARGs are not cumulative, and always refer back to the original acquired position.

2.4.2 Examples
People who are looking for examples of APT files are encouraged to go to http://archive.stsci.edu/hst/abstract.html and do a search for a selection of proposals from the most recent cycle. For any program that appears as though it could serve as a useful example, the APT file can be obtained by typing the proposal ID number into the search form at http://www.stsci.edu/hst/scheduling/program_information Additionally, several examples of ACS dither patterns using POS TARGs which may be used in an APT proposal can be found on the ACS Web site at: http://www.stsci.edu/hst/acs/proposing/dither


Examples and General Advice

19

2.4.3 Common Problems
Incorrect Proposal Format When you are entering text in a field the formats described in this document must be followed exactly, since the information in the forms is interpreted by computer software. Some items that warrant repetition are: · Visit numbers must be unique. · Target names must be spelled exactly the same throughout the proposal. · The format for target positions must be followed to the letter. For more information on coordinates, see Section 3.13 on page 56. · The format for flux data must be followed. Only those defined in these Instructions are acceptable. · The format for Optional Parameters and Special Requirements must be followed to the letter. · Observations which cannot be defined using the syntax in these Instructions may be described in Comments fields, but such comments should be used very sparingly, if at all, and their use may impede execution of a program. Imprecise Target Positions See the discussion of required position accuracies in Table 3.11: Required Coordinate Accuracies. The requirements are much more stringent than is typically the case for ground-based observations. Lack of Acquisition Exposures with Small Apertures When exposures are requested in very small apertures or fields of view, a separate acquisition exposure is generally required. Please consult the Instrument Handbooks for the instrument you are using.

2.4.4 Consideration of Limited Resources
Proposers should be aware that several of the Special Requirements impose serious constraints on the scheduling system because they require the use of limited resources; for example, RT ANALYSIS requires real-time use of the TDRSS that is only available some of the time. Hence these Special Requirements should be requested only if they are absolutely necessary to achieve the scientific goals of a project. It is quite possible that some proposals will be impossible to schedule because of their resource requirements, rather than a lack of scientific merit. The limited-resource Special Requirements can force the planning system to schedule the observations at a less than optimal time. The use of limited-resource


20

Chapter 2: The Basics of Phase II Proposals

Special Requirements by many observers can reduce the overall efficiency with which the planning system can schedule the science program. For these reasons, these Special Requirements should only be used when necessary to achieve the science objectives of the program. The STScI will review the necessity for the Special Requirements and in some cases may suggest removing them, or using alternate methods to obtain the same goal. The following table summarizes the Special Requirements that involve seriously limited resources. The need for many of these Special Requirements must be justified in the Proposal Description. Note that several of these Special Requirements must have been justified in the Phase I Proposal in order to be used legitimately in Phase II; those are CVZ, SHADOW, LOW-SKY, and ON HOLD for Targets of Opportunity.
Table 2.2: Limited-Resource Special Requirements
Limited Resource ON HOLD [FOR ] RT ANALYSIS, REQuires UPLINK ORIENTation TO , SAME ORIENTation AS SHADOW, LOW-SKY, CVZ AFTER , BETWEEN AND , BEFORE , SEQuence WITHIN , SEQuence NON-INTerruptible (replaced by Exposure Group Containers in the APT User Interface); see Section 5.19, "Exposure Containers: Exposure Groups, Coordinated Parallels and Patterns," on page 100, PHASE TO , Reason for constraint Requires special handling (e.g., Targets of Opportunity). Requires real-time TDRSS links, which are difficult to schedule and may be withdrawn at last moment. A specific orientation can be available for as little as a one-week period every six months. Available for only a fraction of orbits.

Constrain scheduling opportunities. Can be mutually incompatible.


Text Proposal File

21

2.5 Text Proposal File
2.5.1 Basic Syntax Rules
Users (particularly RPS2 old-timers) should be aware that some changes to the original RPS2 format were necessary to accommodate enhancements that came with APT; also, some of the syntax has been made stricter in order to make parsing of the file more robust (e.g., for special requirements). Here are a few basic rules that must be followed: · Commas or semicolons must be used to delimit items in a list (see specific rules in the following bullets). New lines for each item will not be sufficient delimiters. · Semicolons must be used to delimit Special Requirements items. · Commas must be used to delimit items in all other lists including target descriptions, target position, fluxes, optional parameters, and spectral elements. · Only the shortest forms of the special requirements will be accepted (e.g., POSition TARGet must be POS TARG). For more information on special requirements see Chapter 7. · Exposure lists in Special Requirements must be specified as a single range. No commas are allowed in an exposure list (e.g., use 1-5 instead of 1,2,3-5). As before, visit lists can have comma delimters. · The Time_Per_Exposure must be specified in seconds. · Dates should be in the form 01-Jan-2005:00:00:00 (as an example) with the hours:minutes:seconds being optional. Other formats will not be supported except for JD, which is used for ZERO-PHASE.

2.5.2 Sample Text Proposal File Template
Your Text Proposal File should include the following and in the order given. Optional blocks are in square brackets ([]). The use of colons is required in the form given. Note that at least one of the three target types (Fixed, Solar System, or Generic) must be present. You can make your own template in APT from your Phase I proposal by opening it in APT and changing it to Phase II. Then enter your Phase II ID number, add a visit, and then export to a text proposal file (If you have already retrieved your proposal from STScI using the Phase II ID given to you by your PC, then the Phase II ID number will have already been filled in).


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Chapter 2: The Basics of Phase II Proposals

Proposal_Information
Title: Proposal_ID: Proposal_Category: Cycle: [Avail_Ok:] [StScI_Edit_Number:]

[Parallel_Information
Parallel_Pointing_Tolerance]

Investigators
PI_Honorific: PI_First_Name: PI_Middle_Initial: PI_Last_Name: PI_Institution: [CoI_Name: CoI_Honorific: CoI_Middle_Initial: CoI_First_Name: CoI_Last_Name: CoI_Institution: [Contact:]]

Abstract Questions
Observing_Description: [Real_Time_Justification:] [Calibration_Justification:] [Additional_Comments:]

[Fixed_Targets
Target_Number: Target_Name: [Alternate_Names:] Description: Position: Equinox:J2000 Coordinate_Source: [RV_or_Z:] [RA_PM:]


Text Proposal File [Dec_PM:] [Epoch:] [Annual_Parallax:] Flux: [Other_Fluxes:] [Comments:]]

23

[Solar_System_Targets
Target_Number: Target_Name: Description: Level_1: [Level_2:] [Level_3:] [Window:] [Ephem_Uncert:] [Acq_Uncert:] Flux: [Other_Fluxes:] [Comments:]]

[Generic_Targets
Target_Number: Target_Name: Description: Criteria: Flux: [Other_Fluxes:] [Comments:]]

[Pattern_Data
Pattern_Number: Primary_Pattern: Pattern_Type: Pattern_Purpose: Number_Of_Points: Point_Spacing: Line_Spacing: Coordinate_Frame: Pattern_Orient: Angle_Between_Sides: Center_Pattern: [Secondary_Pattern: Pattern_Type: Pattern_Purpose: Number_Of_Points: Point_Spacing:


24

Chapter 2: The Basics of Phase II Proposals Line_Spacing: Coordinate_Frame: Pattern_Orient: Angle_Between_Sides: Center_Pattern:] [Pattern_Comments:]]

Visits
Visit_Number: [Visit_Priority:] [Visit_Requirements:] [On_Hold_Comments:] [Visit_Comments:]

Exposure_Number: [Exposure_Label:] Target_Name: Config: Opmode: Aperture: Sp_Element: [Wavelength:] [Optional_Parameters:] Number_of_Iterations: Time_Per_Exposure: [Special_Requirements:] [Sub_Exposures:] [Comments:]


CHAPTER 3:

Fixed and Generic Targets
In this Chapter . . .
3.1 Target Number [Target_Number] 3.2 Target Name [Target_Name and Alternate_Names] 3.3 Target Categor y and Target Description [Description] 3.4 Target Position Type[Position] 3.5 Equinox for Coordinates [Equinox] 3.6 Coordinate Reference Frame [Reference_Frame] 3.7 Radial Velocity or Redshift [RV_ or _Z] 3.8 Is Proper Motion or Parallax Relevant? 3.9 Flux Data [Flux and Other_Fluxes] 3.10 Bright-Object Constraints 3.11 Comments [Comments] 3.12 Generic Targets List [Generic_Targets] 3.13 Getting Coordinates Coordinated / / / / / / / / / / / / / 27 27 31 36 45 45 46 46 47 51 52 53 56

25


26

Chapter 3: Fixed and Generic Targets

Tables and Figures
Table 3.1: Designations of Special Targets Table 3.2: Target Categories Table 3.3: Descriptive Keywords for STAR and EXT-STAR Table 3.4: Descriptive Keywords for STELLAR CLUSTER and EXT-CLUSTER Table 3.5: Descriptive Keywords for GALAXY Table 3.6: Descriptive Keywords for CLUSTER OF GALAXIES Table 3.7: Descriptive Keywords for ISM and EXT-MEDIUM Table 3.8: Descriptive Keywords for UNIDENTIFIED Table 3.9: Descriptive Keywords for CALIBRATION Table 3.10: Discrete Features and Descriptors for All Categories Table 3.11: Required Coordinate Accuracies Table 3.12: Formats for Specification of Target Flux Data Table 3.13: Bright-Object Constraints

The use of "FIXED_TARGETS" and "GENERIC_TARGETS" are described in this chapter. To make the presentation of this material more concise, the section on solar system targets has been made into a separate chapter; see Chapter 4: Solar System Targets on page 59.

The Target List tells us where you wish to point HST and so must be filled out with care, precision, and accuracy. The Target List also provides the information that defines and describe the targets, and which was used to determine exposure times. Three different kinds of Target Lists exist for the following three classes of targets, but only the Target List(s) required for your proposal need be submitted: · Fixed targets (all targets outside the solar system whose positions can be defined by specific celestial coordinates); · Solar-system targets (all moving targets);


Target Number [Target_Number]

27

· Generic targets (targets defined by certain properties, rather than by specific coordinates). In this chapter, each heading has a description followed by a keyword in square brackets (e.g., [Number]). Elsewhere, items in boldface (e.g., RA) show words or phrases that are used as APT Phase II keywords or properties. Items in <> brackets (e.g., ) show values you provide. Values of items listed in square brackets (e.g., [A1: ]) are optional, whereas those not in square brackets are required. As you enter information in the APT interface, you will be told (via a tooltips message) if an item is required.

3.1 Target Number [Target_Number]
Each target in your program will be assigned its own unique number by APT (they are base 10 and go from 1 to 999). A different target must be defined whenever different coordinates or a different target description are required. Separate targets should be defined and listed if you plan to take observations at several points within an extended object. For example, if you were to take spectra at three different locations in the Crab Nebula, each point must have its own target number, name, and coordinates, such as CRAB1, CRAB2, and CRAB3. If you are using the Text Proposal File, all target numbers and names within a proposal must be unique.

3.2 Target Name [Target_Name and Alternate_Names]
Target names provide unique designations for the targets that will be used throughout the proposal. These names will also be used to designate targets in the HST data archive. Prospective proposers and archival researchers use these names to determine whether HST has observed a particular object. This facility will be most useful if consistent naming conventions are used. The following conventions must be followed in naming targets: · A new target name must be defined for each (celestial) target. For example, for several pointings within a galaxy, one might define target names such as NGC4486-NUC, NGC4486-JET, NGC4486-POS1, and NGC4486-POS2.

· The length of a target name must be anywhere from 2 to 31 characters.


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Chapter 3: Fixed and Generic Targets

· No blanks are permitted in target names. Blanks between a letter and a numeral must be suppressed (e.g., HD140283, NGC4378), but a hyphen (and not an underscore) must replace blanks between two letters or two numerals (e.g., ALPHA-CEN, NGC224-0040+4058). Also, a hyphen should be used where required for clarity (e.g., NGC4486-POS1). · Only letters, numerals, hyphens, periods (.), and + or ­ are allowed in target names; other punctuation is not permitted (e.g., BARNARDS-STAR is valid, but BARNARD'S-STAR is not). Greek letters must be spelled out (e.g., ALPHA-ORI). Letters may be upper-case or lower-case, but will always be treated as if they are upper case (e.g. Alpha-Cen will be treated as if written ALPHA-CEN). · Degree signs must be represented by an upper-case "D" (e.g., CD-42°14462 becomes CD-42D14462). · Some special target names are reserved for calibrations and other purposes and may not be used for names of external pointings; see Table 3.1: Designations of Special Targets. Whenever possible, two types of designations should be provided for each target. The first will be a "catalog name" (for example, HD124897), and the second will be at most two "common names" (e.g., ALPHA-BOO, ARCTURUS). The "catalog name" is entered in Name and the "common names" are entered in Alternate_Names. Only Target_Name is used when the target name is repeated in the Visit and Exposure Specifications. If the target is in the STScI Guide Star Catalog (GSC), the GSC name should be included as one of the common names (e.g., GSC5637-12345).

3.2.1 Catalog Name
The preferred order for catalogs to be used for the designation of various classes of objects is provided below. It is arranged in order of decreasing preference. If a target is not contained in these catalogs, other catalog designations may be used (e.g., 4U X-ray catalog designation, Villanova white-dwarf catalog number, etc.). The use of positional catalogs (SAO, Boss, GC, AGK3, FK4, etc.) is discouraged. For uncataloged targets, see Section 3.2.2 on page 29. Stars
1. Henry Draper Catalog number (e.g., HD140283)is preferred. HDE

numbers are discouraged, except in the Magellanic Clouds.


Target Name [Target_Name and Alternate_Names]

29

2. Durchmusterung number (BD, CD, or CPD). In the southern hemi-

sphere, adopt the convention of using CD north of ­52 degrees and CPD south of there (e.g., BD+30D3639, CD-42D14462, CPD-65D7691).
3. General Catalog of Variable Stars designation, if one exists (e.g.,

RR-LYR, SS-CYG).
4. AFGL designation. 5. IRC designation. 6. IRAS designation.

Star Clusters and Nebulae
1. New General Catalog (NGC) number (e.g., NGC6397, NGC7027). 2. Index Catalog (IC) number (e.g., IC418). 3. For planetary nebulae for which you do not have an NGC or IC des-

ignation, the Perek-Kohoutek designation (e.g., PK208+33D1) may be used.
4. For H II regions for which you do not have an NGC or IC designa-

tion, the Sharpless catalog number (e.g., S106) may be used.
5. For IR nebulae, AFGL designation.

Galaxies and Clusters of Galaxies
1. NGC number (e.g., NGC4536). 2. IRAS designation. 3. IC number (e.g., IC724). 4. Uppsala Catalog number, only if an NGC or IC number is not avail-

able (e.g., UGC11810).
5. For clusters of galaxies, the Abell catalog number, but only if an

NGC or IC number is not available (e.g., ABELL2029). Quasars and Active Galaxies
1. The name defined in the compilation by Veron-Cetty and Veron (ESO

Report No. 7, 1989) must be used (e.g., 3C273).

3.2.2 Uncataloged Targets
Objects that have not been cataloged or named must be assigned one of the following designations:


30

Chapter 3: Fixed and Generic Targets 1. Isolated objects must be designated by a code name (the allowed

codes are STAR, NEB, GAL, STAR-CLUS, GAL-CLUS, QSO, SKY, FIELD, and OBJ), followed by a hyphen and the object's J2000 equatorial coordinates, if possible, rounded to seconds of time and seconds of arc (e.g., for a star at J2000 coordinates RA: 1H 34M 28S, DEC: ­15D 31' 38", the designation would be STAR-013428-153138).
2. Uncataloged objects within star clusters, nebulae, or galaxies must

be designated by the name of the parent body followed by a hyphen and the rounded J2000 coordinates, if possible, of the object (e.g., for a target within NGC 224 with J2000 coordinates RA: 0H 40M 12S, DEC: +40D 58' 48", the designation would be NGC224-004012+405848).
3. Positions within nebulae or galaxies may also be designated by the

name of the parent object followed by a hyphen and a qualifier. The qualifier should be brief, but informative (e.g., the jet in NGC 4486 could be designated NGC4486-JET). Other examples are: NGC5139-ROA24, LMC-R136A, ABELL30-CENTRAL-STAR, NGC205-NUC.

3.2.3 Common Names
In addition to the catalog name, a target should be assigned at most two "common names," or aliases, if they exist. Examples of common names are the following:
1. Stars: The Bayer (Greek-letter) designation or Flamsteed number

with standard three-letter constellation abbreviation (e.g., ZETA-CAP, 22VUL, OMICRON2-ERI-B); the Bright Star Catalog number (e.g., HR5270); other names, if they exist (e.g., CYG-X1, BARNARDS-STAR, PROXIMA-CEN).
2. Star clusters, nebulae, galaxies, and clusters of galaxies: Commonly

used names (e.g., HYADES, OMEGA-CEN, CRAB-NEBULA, ABELL63, COMA-CLUSTER); Messier numbers (e.g., M13, M31, M67).

3.2.4 Special Targets
The names of certain types of targets must be designated by appending a code to the target name. For example, -CALIB should be appended to the name of a target that is being observed only as a calibration standard for other observations. These designations will assist in planning of the observing schedule. The possible codes are listed in Table 3.1.


Target Category and Target Description [Description] Table 3.1: Designations of Special Targets
Target Type External calibration target Code -CALIB Description

31

An astronomical target used for calibration (e.g., BD+28D4211-CALIB). Internal calibration sources (e.g., WAVE) and calibrations using the Earth must not be included in the Target List. A target that will be used for an offset acquisition; it is the object that will be acquired first, from which an offset will be applied to move to the target of interest (e.g., 3C273-OFFSET). Two separate exposures must be defined on the Visit and Exposure Specifications; an acquisition of the -OFFSET target, and a science exposure of the (target of interest) program target. The location of the latter target may be specified either by equatorial coordinates or by an offset (see Section 3.4 on page 36). For example: to observe the JET in 3C273, first acquire "stellar-like" source 3C273-OFFSET, then offset to program target 3C273-JET. These are reserved designations and may not be used as the names of external pointing in a target list: ANTI-SUN, ANY, BIAS, CCDFLAT, DARK, EARTH-CALIB, INTFLAT, KSPOTS, NONE, ORBIT-POLE, ORBIT-POLE-NORTH, ORBIT-POLE-SOUTH, UVFLAT, VISFLAT, WAVE

Offset acquisition target

-OFFSET

Special designations

3.3 Target Category and Target Description [Description]
A target description must be selected for each target. The Target Description will be one of the key fields used by archival researchers in searching through the HST data archive; thus it is extremely important that the information be filled out completely and accurately for each target. Each target must be assigned a single primary category from Table 3.2, and at least one descriptive keyword, chosen from the appropriate Table 3.3 through Table 3.9 (see Table 3.2 for which table is appropriate for each category). The discrete features and descriptors in Table 3.10 may be used as descriptive keywords for any category. A maximum of five descriptive keywords may be selected. The categories in Table 3.2, and some of the descriptive keywords in Table 3.3 through Table 3.10, are followed by explanatory text in parentheses. This text is provided only for explanatory purposes and is not part of the category or keyword itself.


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Chapter 3: Fixed and Generic Targets

Text Proposal File If you are using the Text Proposal File, target description items must be separated by commas. Table 3.2: Target Categories
Category SOLAR SYSTEM (Solar System Object) STAR (Galactic Stellar Object) EXT-STAR (Star in an External Galaxy) STELLAR CLUSTER (Galactic Star Cluster, Group, or Association) EXT-CLUSTER (Star Cluster in an External Galaxy) GALAXY (Galaxy or AGN) CLUSTER OF GALAXIES (Galaxy Groupings, Clusters, Large-scale Structure) ISM (Interstellar Medium of the Galaxy) EXT-MEDIUM (Interstellar Medium of an External Galaxy) UNIDENTIFIED (Unidentified Objects) CALIBRATION (Calibration Observations) Descriptive Keywords Discrete Features and Descriptors

Chapter 4: Solar System Targets on page 59 Table 3.3 Table 3.3 Table 3.4 Table 3.4 Table 3.5 Table 3.6 Table 3.7 Table 3.7 Table 3.8 Table 3.9 See Table 3.10

Table 3.3: Descriptive Keywords for STAR and EXT-STAR
Brown Dwarf Wolf Rayet Wolf Rayet ­ WC Wolf Rayet ­ WN Main Sequence O Giant O Supergiant O OE OF SDO WDO F0-F2 F3-F9 FP Late-type Degenerate G V-IV G III-I K V-IV K III-I M V-IV M III-I L Herbig Ae/Be Horizontal Branch Star Interacting Binary X-ray Novae X-ray Burster X-ray Transient LMXB (Low Mass X-ray Binary) Gamma Ray Burster MXB (Massive X-ray Binary) RS CVn Star W UMa Star


Target Category and Target Description [Description] Table 3.3: Descriptive Keywords for STAR and EXT-STAR(Cont)
B0-B2 V-IV B3-B5 V-IV B6-B9.5 V-IV B0-B2 III-I B3-B5 III-I B6-B9.5 III-I BE BP SDB DB DA DC DZ A0-A3 V-IV A4-A9 V-IV A0-A3 III-I A4-A9 III-I AE AM AP AGB Star Post-AGB Star Composite Spectral Type T S Star Carbon Star Long Period Variable Irregular Variable Regular Variable Luminous Blue Variable Dwarf Nova Classical Nova Nova-like Recurrent Nova Polar (AM Her Star) Intermediate Polar (DQ Her Star) Symbiotic Star T Tauri Star FU Orionis Star Shell Star Eta Carinae Star YSO Extra-solar Planet Extra-solar Planetary System Pre-main sequence Star Low Mass Companion Population II Beta Lyrae Star Algol System Barium Star Blue Straggler Neutron Star Pulsar Binary Pulsar FK Comae Star Pulsating Variable PG1159 Star ZZ Ceti Star Cepheid Supernova Supernova Type Ia Supernova Type Ib Supernova Type II RR Lyrae Star Planetary Nebula Central Star Emission Line Star Circumstellar Matter

33

Table 3.4: Descriptive Keywords for STELLAR CLUSTER and EXT-CLUSTER
Globular Cluster Open Cluster Young Association OB Association T Association


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Chapter 3: Fixed and Generic Targets

Table 3.5: Descriptive Keywords for GALAXY
Spiral (Spiral Galaxy) Lenticular (Lenticular Galaxy) Elliptical (Elliptical Galaxy; Not A Dwarf Elliptical) Dwarf Elliptical Magellanic Irregular Amorphous Irregular Dwarf Compact (Dwarf Compact/HII Galaxy) Dwarf Spheroidal BCM (Brightest Cluster Member) BGM (Brightest Group Member) LSB (Low Surface Brightness/HI Rich Galaxy) Seyfert QSO (Radio Quiet) Einstein Ring High Redshift Galaxy (z > 0.5) Quasar (Radio Loud) Radio Galaxy BL Lac (BL Lac or BLAZAR) Liner Starburst Ultraluminous IR Gal Interacting Galaxy Lyman Alpha Cloud Protogalaxy

Table 3.6: Descriptive Keywords for CLUSTER OF GALAXIES
Supercluster Void Group Rich Cluster Poor Cluster High Redshift Cluster (z > 0.5) Galaxy Pair Einstein Ring Blank Sky Interacting Galaxy BCM (Brightest Cluster Member) BGM (Brightest Group Member)

Table 3.7: Descriptive Keywords for ISM and EXT-MEDIUM
Herbig-Haro Object Planetary Nebula HII Region Reflection Nebula Dark Cloud Cometary Nebula Molecular Cloud Bipolar Outflow Absorption Line System Absorption Line System ­ Galactic


Target Category and Target Description [Description] Table 3.7: Descriptive Keywords for ISM and EXT-MEDIUM(Cont)
SNR (Supernova Remnant) Ring Nebula HI Cloud High Velocity Cloud Intermediate Velocity Cloud IRAS Cirrus PDR (Photon Dominated Region) Absorption Line System ­ Extragalactic Damped Lyman Alpha Cloud (Extragalactic) Coronal Gas (105­106 K) Hot Gas (107­108 K) IGM ICM

35

Table 3.8: Descriptive Keywords for UNIDENTIFIED
Radio Emitter Infrared Emitter Optical Emitter Ultraviolet Emitter X-ray Emitter Gamma Ray Emitter Blank Field Parallel Field High Latitude Field Low Latitude Field

Table 3.9: Descriptive Keywords for CALIBRATION
Astrometric Photometric Wavelength Point Spread Function Occulting Finger Location Ion Taled Scattered Light Test Sky Background Instrument Sensitivity Test Narrow Band Filter Calibration FGS Stability Quantum Efficiency Test Pointing and Jitter Test Raster & Step/Dwell Scan Verification Spatial Distortion Test Polarimetry Aperture Location Detector Linearity Test Carrousel Stability Test Target Acquisition Test Detector Sensitivity Test Focus Test Spacecraft Glow Occultation Mode Test Throughput Test Echelle Blaze Function Virtual Pointing FGS Transfer Function Test Shutter Control Test

Table 3.10: Discrete Features and Descriptors for All Categories
Corona Ring Ansae Protoplanetary Disk Disk Bulge Polar Ring Dust Lane BLR (Broad Line Region) NLR (Narrow Line Region) Filament Ejecta


36

Chapter 3: Fixed and Generic Targets Table 3.10: Discrete Features and Descriptors for All Categories(Cont)
Wind Accretion Disk Jet Lobe Hotspot Nucleus Halo Spiral Arm Shell Tidal Tail Bar Multiple Nuclei Cooling Flow Emission Line Nebula Knot Star Forming Region Shock Front Ionization Front Conduction Front Undesignated Gravitational Lens

3.4 Target Position Type[Position]
A position type is required for each fixed target. It may be expressed in any one of three different ways: · By specifying the equatorial coordinates (RA and DEC) of the target; · By specifying a positional offset from another target; or · By specifying a region (area) of the sky. It is also possible to specify that the coordinates were obtained using the Guide Star Selection System (GSSS; see 3.4.5 Determining Coordinates in the Guide Star Selection System (GSSS) Reference System on page 42), or that they are currently uncertain or unknown, and that more accurate coordinates will be provided by the observer after an early acquisition exposure is taken, or in real time during the HST observations. Text Proposal File If you are using the Text Proposal File, target position items must be separated by commas.

3.4.1 Required Accuracies of Target Positions
The HST Scientific Instruments (SIs) typically have very small apertures and fields of view. Target-acquisition apertures for several of the SIs are only a few seconds of arc in size. Since the HST has no analog to the video acquisition cameras common on many ground-based telescopes, it is essential to have accurate coordinates for targets. In many cases targets will be placed in the final observing aperture after a sequence of target-acquisition observations. This will only work, however, if the target


Target Position Type[Position]

37

coordinates are sufficiently accurate and precise to place the target in the first of these acquisition apertures. HST uses two guide stars to stabilize the pointing of the telescope and to place the target in the desired aperture. The fundamental problem, then, is to determine the position of the target relative to the guide stars in the surrounding area with sufficient accuracy to place the target in the aperture. The specific pair of guide stars to be used cannot be determined in advance of the observation; several possible pairs will often be available for each target. The guide stars are chosen from the Guide Star Catalog 2 (GSC2). Over the HST FOV, the relative position errors between guide stars is 0.15" (1 sigma), while the absolute positions on the ICRS have errors of 0.25" (1 sigma). Note that these errors are derived at the epoch of the GSC plate and will increase slowly in time due to proper motion. The accuracies of positions typically needed for target acquisition with each of the SIs are shown in Table 3.11; these are predicated upon the positions being in International Celestial Reference System (ICRS), which is the reference frame of the GSC2 catalog. Note that several of the SIs have multiple acquisition apertures of different sizes that may be used. Be sure when selecting acquisition apertures to keep the coordinate uncertainties in mind. Furthermore, be sure to provide one sigma uncertainties with your positions so that STScI may check the appropriateness of your acquisition exposures. Inaccurate target coordinates can result in failed target acquisitions and can therefore waste valuable HST observing time. As indicated in Table 3.11, it is the observer's responsibility to provide accurate coordinates in all cases, but in particular they must be in the ICRS reference frame when using with the NIC1 and NIC2 detectors. Please contact your PC if you need additional information. Although ICRS frame-based coordinates are not required for FGS and WFPC2 observations, it is still prudent to check the accuracy of your coordinates. All observers will be provided target confirmation charts by their PC to help them verify the target coordinates in the ICRS reference frame. The Principal Investigator of a program is responsible for ensuring that target coordinates are accurate, both at the time of program submission, and later when target confirmation charts are provided. The following address has pertinent information on target confirmation charts:
http://www.stsci.edu/public/confirmation-chart.html

Note: HST proposals executed before July 1991, as well as engineering proposals of type OV, SV, SMOV, and CAL, should not be used to derive target coordinates. Coordinates from such proposals may be unreliable owing to poor calibration and/or engineering-related pointing changes made during the observations.


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Chapter 3: Fixed and Generic Targets

Table 3.11: Required Coordinate Accuracies
Instrument Configuration WFPC2 (WFC) WFPC2 (PC) FGS ACS/SBC NIC11 NIC2 (2) NIC3 (2) Accuracy Required (1 sigma, arcsec) 10 5 1 5 3 5 10 ICRS Coordinates Required? No No No No Yes Yes No

1. If multiple NICMOS detectors are being used in parallel, the primary detector (the detector used for the exposures in the of the PARallel WITH Special Requirement; see PARallel WITH (replaced by Coordinated Parallel Containers in the APT User Interface)) determines the required coordinate accuracy for the observation and whether GSC2 frame-based coordinates are required.

3.4.2 Equatorial Coordinates
If you specify the target position directly in terms of equatorial coordinates (as opposed to specifying an offset or a region), then the right ascension and declination must be provided: RA: RA: +/­ · DEC: DEC: +/­ .

The uncertainties default to 0.1". They should represent the accuracy (1 sigma) of the target coordinates, not the region within which a target could be observed (e.g., for a sky measurement). See 3.4.4 Region of Sky (Extended Targets) on page 41 for instructions on how to designate regions as targets.

· The right-ascension value must be expressed in hours(H), minutes(M), and seconds of time(S). · The declination value must be expressed in degrees(D), minutes ('), and seconds (") of arc. · The units must be selected (from a pull down list) for both the value and its uncertainty. The uncertainty must be expressed in one and only one of the units used to express the related RA and/or DEC, with the additional units of minutes (') of arc or seconds (") of arc


Target Position Type[Position]

39

being allowed for right ascension. (In other words, the RA may be expressed as a combination of three units (HMS), but its uncertainty must be in terms of a single unit such as S or ".) To clarify:
Quantity and units specified RA: H-M-S DEC: D-M-S Acceptable units for uncertainty timemin, timesec, arcmin, arcsec degrees, arcmin, arcsec

Note: If the sign of the declination is not indicated, a positive declination is assumed, but we urge you to always include the sign as a way of reducing errors. Text Proposal File In the Text Proposal File you must use the following format for RA and DEC (note the comma delimiters): RA = +/­ , DEC = +/­ The comma following the right-ascension uncertainty is required. · The right-ascension value must be expressed in hours (H), minutes (M), and seconds (S) of time. The declination value must be expressed in degrees (D), minutes ('), and seconds (") of arc (For example: RA = 12H 7M 13.33S +/­ 0.15S, DEC = +27D 3' 8.0" +/­ 0.1") · Units must be provided for both a value and its uncertainty (see "Acceptable units for uncertainty")

3.4.3 Positional Offsets
The position of a target may alternatively be specified as an offset from a reference target. Note, however, that offsets larger than 30 arcsec may complicate the target acquisition procedure. If larger offsets are desired, please contact your Program Coordinator. Offsets are always in the sense offset = target-coordinates minus offset-reference-coordinates. A polar offset is expressed as an angular separation and position angle of a line drawn from the offset reference target to the target. As with other similar quantities, we urge you to include the sign of the offset, even when it is positive, as a means of removing ambiguity. Note that you select the which has the equatorial coordinates of the reference target, and that reference-target names have ­OFFSET appended to them (see Table 3.1).


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Chapter 3: Fixed and Generic Targets

Positional offsets are only a convenient method of specifying target coordinates, and do not automatically imply a particular method of target acquisition; observers must explicitly specify any target acquisitions on the Visit and Exposure Specifications via Special Requirements (see Chapter 7: Special Requirements [Visit and Exposure Special_Requirements] on page 113).

Warning: If your object has significant proper motion no correction may be applied. See 3.8 Is Proper Motion or Parallax Relevant? on page 46, where it notes that the proper motion for the target is taken to be the same as for the offset object.

You specify the offset as a difference in EQUATORIAL coordinates from a target : Position Type: Offset Offset: RA: DEC: Uncertainty: RA: DEC: From Target:
3. The value for RA offset may be in units of seconds of time or in dec-

imal degrees, and the value for DEC offset may be in units of arcmin (') or arcsec ("), or in decimal degrees (see example below). The uncertainty must be expressed in one and only one of the units used to express the related RA and/or DEC. Offsets in RECTANGULAR coordinates are interpreted as displacements in the tangent plane whose origin is located at the reference target. For displacements of less than about one degree, they may be interpreted as the offsets that are measured on a photographic plate, without making errors larger than about 0.5 arcsec. The format for the specification of an offset in rectangular coordinates is: XI-OFF = +/- , ETA-OFF = +/, FROM Note: North and east displacements are considered positive (+), south and west are negative (­). The values of XI-OFF and ETA-OFF are required to both be expressed in arcmin (') or arcsec ("), and the uncertainties must be expressed in the same units (in other words, all four angular quantities must be in the same units). In the following example, a target has been measured on a sky-survey plate, with a scale of 67 arcsec/mm, to lie 0.5 mm west of, and 1 mm north of, target number 3, with an accuracy of 1 arcsec: XI­OFF = ­33" +/­ 1", ETA­OFF = +67" +/­ 1", FROM 3


Target Position Type[Position] 4. The format for a POLAR offset specification is:

41

R = , PA = , FROM Note that uncertainties must not be included in this type of specification. The separation is expressed in units of minutes (') or seconds (") of arc. The position angle of the target with respect to the reference target is measured east of north, and the unit of measurement (degrees) is required. In the following example, a target lies 10 arcsec from target number 4, at a position angle, measured at target 4 from north through east, of 60 degrees: R = 10", PA = 60D, FROM 4 By default APT provides a value of 0.1" for the uncertainties. Example: NGC2654's right ascension is 2.34 seconds of time less than the reference target (NGC2654-OFFSET), and its declination is 1.6 arcsec greater than NGC2654-OFFSET. The specifications for NGC2654 would be: Position Type: Offset DEC: 1.6" Offset: RA: -2.34S Uncertainty: RA: 0.01S DEC: 0.1" From Target: NGC2654-OFFSET Text Proposal File The format for an offset specification as a difference in equatorial coordinates is: RA-OFF = +/­ , DEC-OFF = +/­ , FROM Note the uncertainties and the commas separating the three items. The value for RA-OFF may be in units of seconds (S) of time, or in decimal degrees (D), and the value for DEC-OFF may be in units of arcmin (') or arcsec ("), or in decimal degrees (D). The uncertainty must be expressed in one and only one of the units used to express the related RA and/or DEC.

3.4.4 Region of Sky (Extended Targets)
Sometimes it is necessary to define a region of sky rather than a specific point. Examples are extended targets (such as emission nebulae and galaxies) and blank-sky regions for background measurements (if it is acceptable to make the observation anywhere within a region). An Equinox value should be specified with the region coordinates (see Section 3.5 on page 45).


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Chapter 3: Fixed and Generic Targets

The units used for regions should be used in the same way as for coordinates; see Section 3.4.2 on page 38. You can choose either a rectangular or a circular region. · Rectangular: Specify the equatorial coordinates and the sides of a rectangle (for RA in arcsec, arcmin, minutes of time or seconds of time; for DEC in arcsec, arcmin or degrees) · Circular: Specify the equatorial coordinates and a radius (in arcsec, arcmin or degrees) Text Proposal File For a rectangular region, the format for equatorial coordinates must be used followed by a comma and the word REGION; the values following +/­ will then be interpreted as one-half the lengths of the sides of the rectangular area, rather than as uncertainties in the coordinates. In the following example, a region 4 arcmin wide in right ascension by 2 arcmin high in declination is specified: RA = 3H 51M 27S +/­ 2', DEC = ­37D 13' 25" +/­ 1', REGION For a circular region, REGION must be followed by another comma and the radius of the region in the format R = ; in this case, no uncertainties should be attached to the RA and DEC. Here is an example of a circular region with a radius of 2 arcmin: RA = 3H 51M 27S, DEC = ­37D 13' 25", REGION, R = 2' Note that the units of R must be specified. Circular Region If it is desired to specify a circular region, REGION must be followed by another comma and the radius of the region in the format R = ; in this case, no uncertainties should be attached to the RA and DEC. Here is an example of a circular region with a radius of 2 arcmin: RA = 3H 51M 27S, DEC = ­37D 13' 25", REGION, R = 2' Note that the units of R must be specified.

3.4.5 Determining Coordinates in the Guide Star Selection System (GSSS) Reference Frame
The HST reference frame is effectively defined by the positions of the Guide Stars that are selected for each pointing. Since launch, we have used the Guide Star Catalog (GSC1) which was an all-sky catalog of stars down to 15th magnitude built from Schmidt Sky Survey plates. This catalog has been updated (GSC2) with more recent epoch plates and calibrated to be on the International Celestial Reference System (ICRS), which has been


Target Position Type[Position]

43

adopted by the IAU as the new fundamental reference frame. This simplifies the procedure for providing HST coordinates since it removes the necessity to tie the object coordinates back to the GSC1 and the plates used to construct it.

For observations that require accurate coordinates, such as those listed as "ICRS Coordinates Required" in Table 3.11, it is vital that you provide positions derived in the ICRS reference frame.

General Guidelines · If your target has a position that is in a catalog using the ICRS you may use the coordinates directly. These include GSC2, Hipparcos, Tycho, SDSS, 2MASS and FIRST. · If your target is an extended object where the observation position does not correspond to the catalog coordinates, we recommend that you obtain an image of the field and measure your target coordinates in the ICRS reference frame. Typically, this is done by measuring a sufficient number of reference stars (for example, from GSC2, Tycho, Hipparcos, 2MASS, SDSS - any catalog that uses the ICRS) to derive your astrometric transformation. · If your target has a relevant proper motion, you must provide the epoch of the coordinate as well as the proper motion values (see Section 3.8, "Is Proper Motion or Parallax Relevant?," on page 46.) · Access to the GSC2, the Digitized Sky Survey (DSS) and other catalogs/surveys is built into the Aladin interface in APT (Note: for the DSS use the POSS2UKSTU-Red plates that were used to build GSC2). You can also find links to query the GSC2 catalog and retrieve POSS2UKSTU-Red DSS images on the HST Support web page at http://www-gsss.stsci.edu/HSTsupport/HSTsupport.htm. Getting Coordinates from the GSC2 or DSS · If your target is a star brighter than m(V)~20 then it typically will be visible on the DSS images and present in the GSC2 catalog. Using the GSC2 position will ensure that the target is in the same reference frame as the selected guide stars. · Please enter the GSC2 name as a target alias in Alternate_Names.


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Chapter 3: Fixed and Generic Targets

· For extended sources visible on the photographic survey plates, we strongly recommend that you examine the DSS image and check your coordinates. Depending on the brightness, morphology and structure of the galaxy the GSC2 coordinate may not correspond to the aperture location you require for your observation. The DSS headers downloaded from STScI contain ICRS-based FITS WCS information to allow you to measure the image using Aladin (or other image analysis tool). · Please note that the GSC2 coordinates for bright stars come from the Tycho2 catalog as these are more accurate than positions measured from the Schmidt plates. · Using coordinates from GSC 1.1 associated special catalogs will be permitted only under exceptional circumstances (contact your Program Coordinator). Other uses of GSC 1.1 are not allowed. Coordinates from the development version GSC 1.2 cannot be used at all as it is not available in the HST ground system. · If you have used HST to observe a target in an earlier cycle and already have GSC1 based coordinates, you also have the option of using a 'Coordinate-Convertor' that is available at the HST Support page. This is a simple web-based tool that allows one to enter either a GSC1 ID or coordinate. In the case of an ID it will directly look up the GSC2 coordinate for that object. If you enter a coordinate, it will derive a mean offset between GSC1 and GSC2 over the HST FOV and apply that correction to the position. As part of preparing your observations your Program Coordinator will provide, as a final check that the coordinates are correct, a Confirmation Chart showing the target coordinates (as entered in the proposal) overlaid on the field from the DSS. Ultimately, you are responsible for verifying that the coordinates are correct (see Section 3.4.1, "Required Accuracies of Target Positions," on page 36).

3.4.6 A Caution on Astrometry Prepared from STScI Plate Scans
Note that the set of plates used to construct the GSC2 coordinates is NOT the same one that is contained in the 102-volume set of CD ROMs distributed as the Digitized Sky Survey (DSS-I). The GSC2 coordinates are primarily derived from the POSS-II Red survey in the northern hemisphere and the AAO-SES/ER Red surveys in the south. These images are only available on-line. If you wish to measure your target coordinates from these images, please download the images using the links from the CASG Web server listed above.


Equinox for Coordinates [Equinox]

45

3.4.7 Early Acquisitions
If it is impossible to obtain adequate plate material to measure coordinates to the required accuracy (for example, a very crowded field which cannot be resolved using ground-based observations), it may be necessary to obtain an early acquisition image or to perform an acquisition that involves real-time interaction with the telescope (see Section 7.3.1 on page 135). In that case, enter coordinates as accurate as possible on the Target List.

3.5 Equinox for Coordinates [Equinox]
The year of the equator and equinox to which the coordinates are referred must be J2000 (Julian).

It is not necessary to apply precession corrections to coordinates from positional catalogs. The Guide Star Catalog and the Hipparcos Input Catalogue both use the J2000 equinox. (Note, however, that the Hipparcos output catalogue is epoch 1991.25, which means proper motions can have significant effects if you are not careful.) For some notes on Equinox, Epoch, and units, see Section 3.13 on page 56.

3.6 Coordinate Reference Frame [Reference_Frame]
This keyword replaces Coordinate_Source starting with Cycle 14 Calibration and all Cycle 15 programs. Select one of the following Reference_Frame values for each target. ICRS To be used if the coordinate reference frame is tied to the International Celestial Reference System (ICRS). Catalogs tied to the ICRS include: HST Guide Star Catalog 2 (GSC2), Hipparcos Catalog and the Tycho-2 Catalog. Other To be used if the coordinates are notICRS.


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Chapter 3: Fixed and Generic Targets

3.7 Radial Velocity or Redshift [RV_ or _Z]
Give, if known, the heliocentric radial velocity or redshift of the target. The format is or ; examples are +1198 (Radial Velocity) and 1.95 (Z). The units must not be specified. Text Proposal File In the Text Proposal File the format is V = +1198 and Z = 1.95.

3.8 Is Proper Motion or Parallax Relevant?
If a small aperture or occulting spot is to be used, even a relatively small proper motion or parallax may cause difficulties in acquiring the target. In such cases, the Proper Motion/Parallax data must be provided. Note, however, that proper motion and parallax values may not be specified for a target which is specified by a positional offset. Such targets will be taken to have the same proper motion and parallax as the reference target. The observer must determine whether or not proper motion or parallax is relevant. In general, this will depend on the size of the acquisition aperture of the SI that will be used and the epoch of the coordinates that have been provided. For example, the STIS uses a target acquisition area of 5 arcsec square. For a star whose coordinates are given for the epoch 1950, and that will be observed in 1997, a proper motion of approximately 0.5*2.5/(1997­1950) = 0.027 arcsec per year would be "relevant," with a resulting offset of half the minimum center-to-edge distance.

3.8.1 Proper Motion and Parallax Data
The following information is required for targets where proper motion and parallax are "relevant"; note that uncertainties for RA_PM, Dec_PM, and Annual_Parallax are not required. If a sign is not given for RA_PM or Dec_PM, a positive value will be assumed, but it is better to be explicit. · RA_PM: For Proper Motion in RA, the value should be in units of seconds of time/year. To convert from arcsec/year to seconds of time/year, divide by 15 cos DEC. · Dec_PM: For Proper Motion in DEC, the value should be in units of arcsec/year. · Epoch: The "Epoch of position" is the date of the "Target Position" which was defined in the Target List (see Section 3.4 on page 36).


Flux Data [Flux and Other_Fluxes]

47

· The "Epoch of position" may or may not be the same as the date of "Equinox for Coordinates" in the Target List (see Section 3.5 on page 45). Remember that the "Epoch of position" is the date the target position is referred to, whereas the "Equinox of Coordinates" is the date of orientation of the coordinate system in which the position is measured. For example, a star with a large proper motion may have its coordinates given in the J2000 system, but the numbers themselves are for epoch 1984, meaning that the star was at the specified position on January 1, 1984. Epoch should be of the form 20yy.y or 19yy.y. · Ordinarily the epoch of position is earlier than the present date. In the Guide Star Catalog (GSC), the equinox is J2000 while the epoch depends on the individual plate. Do not adjust your coordinates to be those that would be measured if the plate were taken in the year 2000. However, some catalogs contain coordinates already adjusted to an epoch of J2000: the Hipparcos Input Catalogue (often used in the GSC for stars brighter than m(V) ~= 9) and the PPM Star Catalog. When these catalogs are being used, it is appropriate to specify an epoch of J2000. (These remarks do not apply to the Hipparcos Output Catalog.) · Annual_Parallax: The unit for parallax is arcsec. The example below is for the object DM­9D697 (Epsilon Eridani), where the proper motion data are taken from the SAO Catalog.
Keyword RA_PM: DEC_PM: Epoch: Annual_Parallax: Explanation Proper Motion in RA Proper Motion in DEC Epoch of Position Annual parallax Units sec/yr arcsec/yr 20yy.y or 19yy.y arcsec Example ­0.0662 0.019 1984.5 0.30488

For some notes on proper motions and units, see Section 3.13 on page 56.

3.9 Flux Data [Flux and Other_Fluxes]
Flux information must be provided for all targets, and there can be more than one entry for a given target. STScI uses flux information to test for over-illumination of sensitive detectors. All entries are values as observed at the Earth, rather than intrinsic values. The flux information is provided in two separate fields:


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Chapter 3: Fixed and Generic Targets

· Flux in V Magnitude with an uncertainty, which is required for targets observed by the FGS and ACS/SBC. For all other instrument configurations, it's optional. · Other Fluxes (separated by commas), which is entered in free text. In the "Other Fluxes" field, the spectral type and color index could be provided if you think it's important. As many additional flux values as appropriate for the requested exposures should be provided. For example, ultraviolet or emission-line fluxes should be given if the target is to be observed in the ultraviolet or through a narrow-band filter, or several magnitudes might be provided if the target is a variable star to be observed at various brightness levels. In some cases (Targets of Opportunity, variable objects, etc.) the estimated flux data may be very uncertain, but the best available estimates should nevertheless be given, along with appropriate uncertainties and comments. It may be important to specify the flux of a background source as well as the target flux. For example, a globular cluster in M87 may be seen against the bright background of the galaxy. The keyword ­BKG should be appended to a background flux specification in this case (see footnote 2 to Table 3.12). Use a comma to separate entries if more than one flux value is given. Flux must be given as F(lambda) rather than F(nu). Recall that the conversion is:
F(lambda) = (3 x 1018 F(nu)) / lambda2,

where lambda is in ångstroms and F(nu) is in erg/(cm2 sec Hz). For example, if lambda = 1500å, and F(nu) = 1.0 x 10-26, then F(lambda) = 1.3 x 10-14. The flux data are to be expressed in the format shown in Table 3.12. Do not enter explicit units. Text Proposal File If you are using the Text Proposal File, flux items in a list must be separated by commas.

3.9.1 General Guidelines on What Flux Data to Include
The following summary provides general guidelines for what flux information must be included in five general cases. See the Instrument Handbooks for more detailed descriptions of how to make the exposure time calculations.


Flux Data [Flux and Other_Fluxes]

49

Point source, non-dispersive instrument
1. Target flux: V magnitude, (B­V), E(B­V), spectral type.

Flux at specified wavelength may be substituted for V magnitude. If no entry for E(B­V) is given, E(B­V) = 0 will be assumed.
2. Background (optional): Broad-band surface brightness or surface

brightness at specified wavelength; ­BKG must be specified in the name of the flux parameter.
3. Flux in wavelength range of observation.

Extended source, non-dispersive instrument
1. Target flux: V surface brightness, (B­V), E(B­V).

Flux at specified wavelength may be substituted for V surface brightness. If no entry for E(B­V) is given, E(B­V) = 0 will be assumed.
2. Background (optional): Broad-band surface brightness or surface

brightness at specified wavelength; ­BKG must be specified in the name of the flux parameter.
3. Surface flux at wavelength of observation and size of the region spec-

ified. Point source, dispersive instrument
1. Target flux: V magnitude, (B­V), E(B­V), spectral type.

Flux at specified wavelength may be substituted for V magnitude. If no entry for E(B­V) is given, E(B­V) = 0 will be assumed.
2. Background (optional): Surface brightness of continuum; ­BKG

must be specified in the name of the flux parameter.
3. Continuum flux in wavelength range of observation. 4. Line flux and line width of brightest emission line in the wavelength

range of observation. Extended source, dispersive instrument
1. Target flux: V surface brightness, (B­V), E(B­V).

Flux at specified wavelength may be substituted for V surface brightness. If no entry for E(B­V) is given, E(B­V) = 0 will be assumed.
2. Background (optional): Surface brightness of continuum; ­BKG

must be specified in the name of the flux parameter.
3. Surface flux at wavelength of observation and size of the region spec-

ified.


50

Chapter 3: Fixed and Generic Targets 4. Line surface flux and line width of brightest emission line in the

wavelength range of observation. Infrared source
1. Target flux: J magnitude, (J­K). Flux at specified wavelength may be

substituted for J magnitude.
2. Background (optional): Broad-band surface brightness at specified

wavelength; ­BKG must be specified in the name of the flux parameter.
3. Note that this refers to the astronomical background and not the ther-

mal background.
4. Flux in wavelength range of observation. Note that this must be in units of erg/(cm2 sec å). The NICMOS units conversion tool on the

STScI WWW pages can help you convert your source flux from J magnitude or flux in Janskys into this flux unit.

Note: Details of how the above flux information was derived must be given in the proposal text section in the Observing_Description (see the Call for Proposals). If any of the required flux data cannot be provided or are deemed to be unnecessary, these points must also be explained in that section. Incomplete flux information may delay the implementation of your proposal.

Table 3.12: Formats for Specification of Target Flux Data
Parameter Examples for Stars: Broad-band magnitude1 Spectral type Color Index1 Color Excess Background Surface Brightness2 V=13.1 +/­ 0.5 TYPE=G5III B-V = 0.86 +/­ 0.2 E(B-V) = 0.3 +/­ 0.2 SURF-BKG(B) = 20 +/­ 0.2 magnitude magnitude mag/arcsec2 magnitude Format example Units

Examples for Galaxies, Nebulae, and other extended sources:


Bright-Object Constraints Table 3.12: Formats for Specification of Target Flux Data(Cont)
Parameter Surface Brightness1,2 Surface Brightness1 Color Excess Format example SURF(V) = 25.0 +/­ 1.0 SURF(B) = 24.5 +/- 0.5 E(B-V) = 2.5 +/­ 0.2 Units mag/arcsec2 mag/arcsec2 mag

51

Plus whatever other fluxes are relevant to your science program. Some other examples are listed below: Interstellar Extinction Flux at a specified wavelength Continuum Flux3 Line Flux3,4,5 Line Width6 Surface Brightness at specified wavelength2 Surface Brightness at continuum wavelength2 Surface Brightness of line emission3,4,5 Size (FWHM of circular region)7 A(V) = 1.3 +/­ 0.1 F(5100) = 51 +/­ 3 E-15 F-CONT(3500) = 57 +/­ 3 E-15 F-LINE(3727) = 5 +/­ 1 E-14 W-LINE(3727) = 2.4 +/­ 0.2 SURF(5100) = 11 +/­ 2 E-15 SURF-CONT(5000) = 52 +/­ 2 E-15 SURF-LINE(5007) = 52 +/­ 2 E-15 SIZE = 25 +/­5 mag erg/(cm2 sec å) erg/(cm2 sec å) erg/(cm2 sec å) å erg/(cm2 sec å arcsec2) erg/(cm2 sec å arcsec2) erg/(cm2 sec arcsec2) arcsec

1. The following broad-band magnitudes may be used: U,B,V,R,I,J,H,K. 2. You may append "­BKG" to this reference (just before the wavelength designation) to indicate that it is a background flux value (e.g., SURF-BKG(V) = 18.2 +/­ 0.5; SURF-CONT-BKG(5100) = 10 +/­ 3 E-15). 3. Give wavelength used in keyword in rest frame, but flux in observed frame. 4. Line flux should be relative to the continuum, if specified, or relative to zero if not specified. 5. Whenever the S/N refers to a spectral line, W-LINE must be given along with F-LINE or SURF-LINE. Values of F-LINE and SURF-LINE outside the Earth's atmosphere are required. 6. W-LINE is the full width at half maximum (FWHM). 7. SIZE should be included if the exposure time estimate assumed the flux was spread over an extended region; if omitted, the highest spatial resolution of the observing mode will be assumed.

3.10 Bright-Object Constraints
Several of the Scientific Instruments must be protected against over-illumination. Table 3.13 summarizes the safety restrictions by


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Chapter 3: Fixed and Generic Targets

instrument. You should not propose observations which violate these guidelines. Non-linearity, saturation, or other temporary effects which may occur at substantially fainter limits than those identified below are described in the Instrument Handbooks. APT contains a Bright Object Tool (BOT) that can be used to check on these constraints. Proposers should check both the target and the entire field (35" radius from the target for a single default pointing at any orientation, larger plus 5" buffer with POS TARGs or other displacements), using the Aladin interface provided in APT.
Table 3.13: Bright-Object Constraints
Instrument ACS Description The ACS/SBC MAMA detector is subject to strict bright-object controls to prevent potentially fatal damage. Maximum permissible local and global count rates have been established for both imaging and spectroscopy; see the ACS Instrument Handbook (Section 7.5). These limits have been translated into a table of magnitudes as a function of spectral type for the various configurations and modes (ACS Instrument Handbook, Table 7.8). Some of these limits are quite faint. All potential targets should be checked for safety with the ACS Exposure Time Calculator on the Web. Measured UV fluxes must be provided for any objects within 1 magnitude of the spectroscopic limits. This requirement extends to both targets and field objects on the detector. ORIENTs and/or POS TARGs may be used to avoid the latter. Unless they can be screened with GSC2/DSS, magnitudes and colors, or a UV image, must be provided for all objects in the fields of proposed SBC observations, including the background fields of solar-system targets. There are no safety-related brightness limits for the WFPC2. See the WFPC2 Instrument Handbook for a description of saturation levels, residual charge, etc. The FGS may not be used to view objects brighter than mV = 1.8. The FGS may view objects brighter than mV = 8.0 only if the neutral-density filter is in place. There are no safety-related brightness limits for the NICMOS. See the NICMOS Instrument Handbook for a description of saturation levels, residual charge, etc.

WFPC2 FGS

NICMOS

3.11 Comments [Comments]
Information that cannot be made to conform to the required formats may be entered in "Comments" area. Comments are not interpreted by the software, but are maintained in the data base and do appear on printouts of the forms.


Generic Targets List [Generic_Targets]

53

3.12 Generic Targets List [Generic_Targets]
Generic targets are those that can only be described in terms of astronomical characteristics or general location in the sky. This category is used only for Targets of Opportunity and parallel exposures. For parallel exposures, both pure-parallel and coordinated-parallel (see Chapter 6: Parallel Science Exposures on page 103), the pointing is determined by the primary observation, and the specification of a generic target for the parallel exposure denotes a region within which the parallel aperture is expected to point. If the parallel pointing does not matter and the intent is simply to sample whatever the parallel aperture happens to detect, it is not necessary to define a generic target; instead the special target ANY should be used (see 5.8 Target Name [Target_Name] on page 94). Generic targets or target ANY (see Table 5.1: Special External Target Names) should only be used in one of these three cases:
1. The exposure is a coordinated parallel or SAME POS AS another

exposure (so that the pointing is determined by the other exposure), or
2. The visit is a pure parallel (in which case the target will be matched

against already-scheduled observations), or
3. The visit is ON HOLD (as with Targets of Opportunity, for exam-

ple). In this case the target should be replaced by a fixed target when the ON HOLD is removed. Note: Generic Target region coordinates are assumed to be in the J2000 reference frame.

3.12.1 Target Number(s) [Target_Number]
The target number will be assigned by the APT software. If you are using the Text Proposal File, generic targets should be given individual names and numbers just like fixed targets.

3.12.2 Target Name [Target_Name]
A descriptive name must be provided for each target. If a name cannot be specified in advance, a provisional name should be supplied. When the actual observation is made, a more specific name will be added to the target designation. Either the provisional name or the updated name can then be used for archival searches (e.g., SN might be the provisional name, while


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Chapter 3: Fixed and Generic Targets

SN-1995D might be the updated name). A unique target name must be assigned to each generic target.

3.12.3 Target Description [Description]
See Section 3.3, "Target Category and Target Description [Description]," on page 31.

3.12.4 Flux Data [Flux]
See Section 3.9, "Flux Data [Flux and Other_Fluxes]," on page 47. Flux data are not required for pure parallel observations of generic targets.

3.12.5 Comments [Comments]
See Section 3.11, "Comments [Comments]," on page 52.

3.12.6 Generic Target Specifications [Criteria}
The "Criteria" field is a way to specify generic celestial regions and target lists is described below, and should be used for Generic Targets. These instructions should be followed in order for pure parallels with generic targets to be schedulable. Two types of generic target specifications are permitted: · Region generic targets: a celestial region specified in one of three coordinate systems · Target Lists: lists of fixed or generic targets The Selection Criteria field should use the syntax specified below whenever the selection criteria can be fully specified by a celestial region in one of the supported coordinate systems, or by a list of fixed or generic targets. Region Generic Targets Three coordinate systems are supported: · Equatorial: right ascension (RA) and declination (DEC) · Galactic: Galactic longitude (LII) and Galactic latitude (BII) · Ecliptic: ecliptic longitude (LAMBDA) and ecliptic latitude (BETA) Regions may be any of:
1. "Rectangular" regions, i.e. bounded by latitude and longitude limits

in the appropriate coordinate system


Generic Targets List [Generic_Targets]

55

2. Circular regions, specified as within some angular limit of a point

specified in any of the three supported coordinate systems
3. Polar caps or equatorial bands in any supported coordinate system

The following table provides examples of each of these types of region specifications. Note that the same rules for specifying RA and Dec apply as for fixed targets ( Section 3.4.2 on page 38) and that the angle specifications must include ' and " (or M and S).

Region type rectangular

Equatorial coordinates RA = 5H 30M 0S +/180M, DEC = -65D 0' 00" +/- 10D

Galactic coordinates LII = 45D 0' 00" +/-10D, BII = 15D 0' 00" +/-10D LII = 0D 0' 00", BII = 15D 0' 00", R=5D BII < -30D 0' 00" ABS_BII > 30D 0' 00" ABS_BII < 30D 0' 00"

Ecliptic coordinates LAMBDA = 56D 0' 00" +/-5D, BETA = 60D 0' 00" +/-15D LAMBDA = 45D 0' 00", BETA = -15D 0' 00", R = 5.5D BETA > 10D 0' 00" ABS_BETA > 10D 0' 00" ABS_BETA < 45D 0' 00"

circular

RA = 1H 30M 0S, DEC = -15D 0' 0", R=10D

polar cap both polar caps equatorial band

DEC > 60D 0' 0" ABS_DEC > 60D 0' 0" ABS_DEC < 10D 0' 0"

Note that for rectangular and circular regions, the syntax is identical to that of fixed target regions except that the indicator REGION is omitted, and galactic and ecliptic coordinates are allowed. Target Lists In some cases it may be desirable to specify as a Generic Target any of a list of Fixed Target positions or Generic Target regions. In this case the fixed targets should be provided as usual on the Fixed Target List, and the generic target regions should be specified as above on the Generic Target List. Then a new generic target can be defined with Selection Criteria specified by: TARGETS = This will be taken to indicate that any of the targets in are suitable as targets. Note that target numbers are required to be unique across all targets in a proposal, whether on the Fixed, Generic, or Solar System Target Lists.


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Chapter 3: Fixed and Generic Targets

This type of target is particularly useful when a known list of objects of interest is available, and it is desired to observe one of these objects with an imaging SI when a primary exposure with a spectrograph is positioned appropriately nearby.

3.13 Getting Coordinates Coordinated
Observers are responsible for the accuracy and appropriateness of the coordinates they supply and any changes made to them. Only you can determine where we should point HST. Equinox is always a critical quantity when specifying coordinates. All astronomical coordinates change with time because of the precession of the Earth's rotation axis. Equinox specifies a time to which a coordinate system is tied. Thus J2000 refers to the location of an object in celestial coordinates for the coordinate reference frame of January 1, 2000. Epoch is generally important only for objects that move. In particular, the epoch of a star's coordinates refers to a specific time at which the star is at that location. For example, the Hipparcos output catalogue lists coordinates of the brighter stars in the ICRS reference system (which is very nearly the same as J2000), and the coordinates themselves are for epoch 1991.25. The proper motions in the Hipparcos output catalogue are also epoch 1991.25, the midpoint of the mission. If you specify the epoch and equinox correctly, we can easily compute the location of an object at the time it will be observed with HST. (Note: An epoch is purely a time, and one of the form "J1991.25" is nonsensical.) Proper motions sometimes cause problems. Units are especially crucial. The proper motion in Right Ascension (RA_PM) is to be listed in sec/yr, meaning seconds of time per year. If you have a value for RA_PM in arcsec per year, you need to divide it by 15 (to convert from arcsec to time sec), and to then divide by cos because lines of constant RA converge in going to the poles. DEC_PM is almost always listed in arcsec/yr, which are the units needed for HST observing. As we have emphasized above, we urge you to use signs on quantities, even when they are not required. A value of +0.060 for RA_PM, say, makes it clear that the sign has been considered. Just specifying 0.060 leaves ambiguity because sometimes observers forget a minus. One more thing: be very careful if your target lies near a celestial pole. Many precession routines break down in this regime, and uncertainties in position can cause problems too. Also, patterns that you may execute with an instrument could cross the pole, leading to confusion in position. All these issues can be resolved, but careful attention is needed.


Getting Coordinates Coordinated

57


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Chapter 3: Fixed and Generic Targets


CHAPTER 4:

Solar System Targets
In this chapter . . .
4.1 Target Number [Target_Number] 4.2 Target Name [Target_Name] 4.3 Target Description [Description] 4.4 Target Position 4.4.1 Target Position Level 1 [Level_1] 4.4.2 Target Position Level 2 [Level_2] 4.4.3 Target Position Level 3 [Level_3] 4.5 Ephemeris Uncer tainty [Ephem_Uncer t] 4.6 Acquisition Uncer tainty [Acq_Uncer t] 4.7 Obser ving Windows [Windows] 4.8 Flux Data [Flux and Other_Fluxes] 4.9 Comments [Comments] 4.10 Illustrations of Orbital Longitude 4.11 Examples of Target List Blocks / / / / / / / / / / / / / / 61 62 64 65 67 69 75 75 76 76 82 84 84 85

59


60

Chapter 4: Solar System Targets

Tables and Figures
Table 4.1: Solar System Standard Targets Table 4.2: Target Description Keywords Table 4.3: Positional Parameters for TYPE = COMET Table 4.4: Positional Parameters for TYPE = ASTEROID Table 4.5: Parameters for TYPE = PGRAPHIC Table 4.6: Parameters for TYPE = POS_ANGLE Table 4.7: Parameters for TYPE = MAGNETO Table 4.8: Parameters for TYPE = TORUS Table 4.9: Parameters for TYPE = SAT Table 4.10: Parameters for TYPE = PCENTRIC Table 4.11: Keywords for Obser ving Windows Table 4.12: Operators for Obser ving Windows Table 4.13: Formats for Specification of Target Flux Data Figure 4.1: Orbital Longitude for Satellites / 84 Figure 4.2: Orbital Longitude for Planets / 85

HST is able to point at and track solar system targets with sub-arcsecond accuracy. In order for target acquisition and tracking to succeed, planetary observers must specify positions for their targets in a precise and unambiguous manner. Therefore, it is imperative that the Solar System Target List (SSTL) be carefully and correctly completed. This section explains how to fill out the SSTL for any solar system target. Ephemerides are generated using fundamental ephemeris information from NASA's Jet Propulsion Laboratory (JPL). Ephemerides can be generated for all known types of solar system targets, including planets, satellites, comets, asteroids, surface features on planets and satellites, and offset positions with respect to the centers of all the above bodies. The following instructions demonstrate how to define solar system targets in a way that allows accurate ephemeris generation. The body-axes definitions, body dimensions, directions of rotation poles, rotation rates, and the definitions of cartographic coordinates used by STScI are normally identical to the values adopted in the report of the


Target Number [Target_Number]

61

"IAU Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites: 1982" (Davies, M.E., et al., Celestial Mechanics, 29, 309-321, 1983). In a few instances, the latter data have been updated due to new results obtained from the flyby spacecraft. Also, some new bodies have been added which were unknown at the time of the IAU report. For Jupiter and Saturn, the lambda(III) coordinate system is assumed, but lambda(I) or lambda(II) can be used. For Uranus and Neptune, coordinates follow the "Report of the IAU/IAG/COSPAR Working Group on Cartographic Coordinates and Rotation Rates of the Planets and Satellites" (Celestial Mechanics and Dynamic Astronomy, 46, 197, 1989). If you need further information on these, please contact your Program Coordinator. One exception exists to the requirements outlined above. Observers for solar system Targets of Opportunity (e.g. a "new" comet or asteroid, a solar-wind disturbance reaching the Jovian magnetosphere, etc.), should complete the Generic Target List (See "Generic Targets List [Generic_Targets]" in Chapter 3.) and the Visit and Exposure Specifications (to the extent possible) in time for the Phase II deadline. If and when a suitable target appears, the proposer must complete the Solar System Target List and update the Visit and Exposure Specifications. No target can be observed until the complete Phase II information is provided. In this chapter, each heading has a description followed by a keyword in square brackets (e.g., [Target_Number]). Elsewhere, items in boldface (e.g., RA) show words or phrases that are used as APT Phase II items or properties. Items in <> brackets (e.g., ) show values you provide. Items listed in square brackets (e.g., [A1 : ]) are optional, whereas those not in square brackets are required. As you enter information in the APT interface. You will be told (via a tooltips message) if an item is required, and its format.

4.1 Target Number [Target_Number]
Each target must have a unique target number (base 10 from 1 to 999) and are usually assigned by the APT software. Target numbers must be positive, monotonically increasing integers. You should define a different target whenever a different target position or timing description is required. For example, separate targets should be defined if you plan to take spectra of several different surface features on a planet, or if you plan to observe the same feature with different timing constraints.


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Chapter 4: Solar System Targets

4.2 Target Name [Target_Name]
The name is used to identify a target; all target names within a proposal must be unique. The target name can be selected from the STScI list of standard targets (see Table 4.1; explanations of "Level 1" and "Level 2" are given below), or a name can be defined by the GO. The use of standard names is encouraged whenever possible. The following conventions should be followed in naming targets: · The length of a target name can be anywhere from 2 to 31 characters. · No blanks are permitted in target names. A hyphen should replace blanks that would normally be used to separate fields (e.g. IO-TORUS, COMET-BRADFIELD-1979X). · Only letters and numerals are allowed in target names; punctuation (other than hyphens and + or ­) is not permitted. · Construct target names so they make sense for your observing program. For example, if your program consisted of consecutive observations of three surface features on Mars, then three appropriate target names might be: MARS-FEATURE1, MARS-FEATURE2, and MARS-FEATURE3.

Do not use just a standard name for a target when a specific portion of a body is being observed. For example, do not use "Saturn" as the target name for a feature or specific location that is defined relative to the position of Saturn as a standard body because this is confusing for the software that computes the positions of moving targets.

Table 4.1: Solar System Standard Targets
Level 1 Sun Mercury Venus Earth Mars Moon Phobos Hubble Deimos Level 2


Target Name [Target_Name] Table 4.1: Solar System Standard Targets (Cont)
Level 1 Jupiter Level 2 Io Callisto Elara Lysithea Leda Metis Taygete Kalyke Isonoe Thyone Eurydome Orthosie Megaclite Mneme Arche Carpo Saturn Mimas Dione Hyperion Janus Telesto Prometheus Paaliaq Suttungr Albiorix Siarnaq Narvi Polydeuces Europa Amalthea Pasiphae Carme Thebe Callirrhoe Chaldene Iocaste Praxidike Hermippe Euanthe Sponde Pasithee Aoede Kallichore Eukelade Enceladus Rhea Iapetus Epimetheus Calypso Pandora Tarvos Kiviuq Skathi Thrymr Methone Daphnis Ganymede Himalia Sinope Ananke Adrastea Themisto Harpalyke Erinome Autonoe Aitne Euporie Kale Hegemone Thelxinoe Helike Cyllene Tethys Titan Phoebe Helene Atlas Pan Ijiraq Mundilfari Erriapo Ymir Pallene

63


64

Chapter 4: Solar System Targets Table 4.1: Solar System Standard Targets (Cont)
Level 1 Uranus Level 2 Ariel Oberon Ophelia Desdemona Rosalind Caliban Setebos Francisco Perdita Neptune Triton Thalassa Larissa Psamathe Neso Pluto Charon Nix Hydra Umbriel Miranda Bianca Juliet Belinda Sycorax Stephano Margaret Mab Nereid Despina Proteus Sao Titania Cordelia Cressida Portia Puck Prospero Trinculo Ferdinand Cupid Naiad Galatea Halimede Laomedeia

If you are uncertain whether or not your target can be referenced by name, contact your Program Coordinator for guidance.

4.3 Target Description [Description]
The target description is used to sort the solar system targets by class and will be useful to archival researchers. The first word in any target description must be one of the + listed below. The keyword is then followed with text that depends on the target class as described below.
Table 4.2: Target Description Keywords
Keyword PLANET SATELLITE Description If the target is the center of a planet, enter PLANET followed by the name of the planet (e.g., PLANET JUPITER, PLANET SATURN). If the target is the center of the satellite of a planet, enter SATELLITE followed by the satellite name (e.g., SATELLITE GANYMEDE, SATELLITE 1980S27)


Target Position Table 4.2: Target Description Keywords (Cont)
Keyword COMET Description

65

If the target is the nucleus of a comet, enter COMET followed by its common name or catalog designation (e.g., COMET HALLEY, COMET 1979X) If the target is the center of an asteroid, enter ASTEROID followed by its common name or its catalog number (e.g., ASTEROID CERES, ASTEROID 452) If the target is a surface feature, enter FEATURE followed by the name of the parent body (e.g., FEATURE JUPITER, FEATURE IO) If the target is an offset position with respect to a solar system body (but not a feature on its surface), enter OFFSET followed by the name of the parent (reference) object (e.g., OFFSET COMET HALLEY, OFFSET JUPITER) If the target is in a ring, enter RING followed by the name of the parent object (e.g., RING JUPITER, RING SATURN) If the target is a plasma torus, enter TORUS followed by the name of the parent object (e.g., TORUS JUPITER) If your target cannot be classified under any of the categories above, then enter OTHER followed by some description of the type of observation planned (e.g., ASTROMETRIC REFERENCE, INTERPLANETARY MEDIUM, ZODIACAL LIGHT)

ASTEROID

FEATURE OFFSET

RING TORUS OTHER

4.4 Target Position
Target Pointing Specification (TPS) and "Levels" Three fields are used to describe the target's position, referred to here as the Target Pointing Specification (TPS). The TPS has been defined using a hierarchical structure. · Level 1 refers to a target in orbit about the Sun. Examples of Level 1 targets include planets, asteroids, and comets. When a Level 1 object is the desired target for observation, complete the Level 1 field and leave the other two target position fields blank. · Level 2 refers to a target whose motion is normally described with respect to a Level 1 object. Examples of Level 2 targets include planetary satellites, surface features on planets or asteroids, and non-nuclear positions in the coma of a comet. When a Level 2 object is the desired target for observations, the Level 1 field contains information on the parent body, and the Level 2 field gives positions relative to this body. In this case, leave the Level 3 field blank.


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Chapter 4: Solar System Targets

· Level 3 refers to a target whose motion is normally described with respect to a Level 2 object. Examples are a surface feature on a planetary satellite or a pointing which is offset from the center of a planetary satellite. When a Level 3 object is the desired target for observation, then all three fields must be completed, with Level 1 giving the parent of the body described in Level 2, and Level 3 giving the position of the observed target with respect to the body in Level 2.

No more than three levels are allowed. If you believe that your target cannot be described in this form, contact your Program Coordinator.

Text Proposal File If you are using the Text Proposal File, TPS items must be separated by commas. Describing Targets The targets specified in the target position fields can be described in up to four ways: · By a name selected from a list of targets · By orbital elements · By coordinates with respect to another object · Via target selection during a real-time observing session Table 4.1 gives the list of valid names for solar system targets. PIs are responsible for obtaining up-to-date orbital elements for bodies not in this table. Objects must be denoted by their IAU-adopted name. A good reference for object names can be found in the Astronomical Almanac, and in the Marsden comet catalog (Marsden, B. G., Catalog of Cometary Orbits, Enslow Publishers, Hillside, NJ, 1983). If you are uncertain whether or not your target can be referenced by name, contact your Program Coordinator. In those cases where the target's position is given with respect to one of the standard objects, the latest available data from JPL on the bodies' physical dimensions, orientation, and rotation rates are used in calculating the target's position. In those cases where all or part of the TPS for your target can be described using standard names, we strongly recommend that you do so. Generally, this will result in the most accurate ephemeris generation for your target.


Target Position

67

Specifying Time Wherever there is an entry involving time, the format for that entry must be: DD-MMM-YYYY:hh:mm:ss.s, where DD is the day of the month, MMM is the first three letters of the month name, YYYY are the full four digits of the Gregorian calendar year, hh is the hour, mm is the minute, and ss.s are the decimal seconds. Only the necessary precision need be specified (NOTE: But the time after the colon it must be completely specified or not at all) Examples: 02-AUG-1993:13:04:31 15-JAN-1994 Two different systems of time are used in this document. TDB refers to Barycentric Dynamical Time and can be considered synonymous with ET (Ephemeris Time), which was used before 1984. UTC refers to Coordinated Universal Time. The precise interpretation of each time value depends on the context in which it is used.

4.4.1 Target Position Level 1 [Level_1]
Specify your target in this field in one of the following ways:
1. STD =