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Version 9.1 October, 2005

Wide Field and Planetary Camera 2 Instrument Handbook Update for Cycle 15

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Information and other resources are available at the STScI World Wide Web site: · URL: http://www.stsci.edu/hst and at the WFPC2 web site: URL:http://www.stsci.edu/instruments/wfpc2/wfpc2_top.html

Revision History
Instrument WF/PC-1 WF/PC-1 WFPC2 WFPC2 WFPC2 WFPC2 WFPC2 WFPC2 WFPC2 WFPC2 WFPC2 WFPC2 WFPC2 Version 1.0; 2.0; 2.1 3.0 1.0; 2.0; 3.0 4.0 Update Update 5.0 6.0 6.1 7.0 8.0 9.0 9.1 Date October 1985; May 1989; May 1990 April 1992 March 1993; May 1994; June 1995 June 1996 June 1998 June 1999 June 2000 June 2001 July 2001 October 2002 October 2003 October 2004 October 2005 Editor Richard Griffiths John W. MacKenty Christopher J. Burrows John A. Biretta Andrew Fruchter, Inge Heyer Stefano Casertano John A. Biretta, Inge Heyer John A. Biretta, Inge Heyer John A. Biretta, Inge Heyer John A. Biretta, Lori M. Lubin Anton Koekemoer, Inge Heyer Inge Heyer, John A. Biretta Inge Heyer, John A. Biretta

Send comments or corrections to: Space Telescope Science Institute 3700 San Martin Drive Baltimore, Maryland 21218 E-mail:help@stsci.edu


CHAPTER 1:

WFPC2 Instrument Handbook Update
In this book. . .
1.1 WFPC2 and Two-Gyro Mode 1.2 STIS Availability 1.3 Photometric Stability 1.4 Cycle 14 WFPC2 Calibration Plan / / / / 1 2 2 4

1.1

WFPC2 and Two-Gyro Mode
Two-gyro mode is expected to have no impact whatsoever on WFPC2 imaging performance. This expectation is based largely on extensive on-orbit imaging tests carried out with both ACS and WFPC2 in February 2005. The gyro set and implementation details will be somewhat different between the February 2005 test and GO observing, so there is some remote possibility of unexpected effects. Additional tests are planned in August 2005 to address these concerns. There are, however, significant impacts from two-gyro mode on target scheduling. These are discussed in the HST Two-Gyro Handbook and are implemented in the APT planning tools. HST fine-pointing and instrument performance in two-gyro mode is expected to be indistinguishable from the performance observed in three-gyro mode.

1


2

Chapter 1: WFPC2 Instrument Handbook Update

1.2

STIS Availability
While the full version of WFPC2 Instrument Handbook (Cycle 14) compares the properties of WFPC2 and STIS, observers are of course reminded that STIS is no longer available.

1.3

Photometric Stability
The long-term photometric stability of WFPC2 has been evaluated by examining the photometric monitoring data collected over the lifetime of the instrument. Our primary standard, GRW+70D5824, has been observed roughly every four weeks, before and after decontamination procedures, both in the far UV and in the standard photometric filters. Early observations were taken monthly in both the PC and WF3. Observations starting in Cycle 6 were on a rotating schedule, where observations are taken in a different chip each month. Since Cycle 11 (starting Fall 2002) these observations are taken every 49 days either before or after a decontamination procedure, and starting in Cycle 14 they will be taken every 55-60 days due to the more limited target visibility resulting from 2-gyro mode. Figure 1.1 on page 3 shows the photometric monitoring data for the standard star GRW+70D5824 (a white dwarf classified DA3; B-V = -0.09) in the WF3 and PC1 for the set of filters which are routinely monitored. Only data after April 24, 1994, when the CCD operating temperatures were lowered from -76°C to -88°C, are shown.


Photometric Stability Figure 1.1: Photometric Monitoring Data for WFPC2.

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4

1.4
goals of the to maintain in Cycle 14 to the more Cycle 14 WFPC2 Calibration Programs are to monitor health and safety of the required calibration accuracies for the science modes used in Cycle 14. As noted the decontamination procedures (and attendant observations) are performed every limited target visibility resulting from 2-gyro mode.

Cycle 14 WFPC2 Calibration Plan

The overall instrument and above, starting 55-60 days due
Table 1.1: WFPC2 Cycle 14 Calibration Plan.
Estimated Time (orbits) Frequency "External" Decons every 50-60d 6 94 every 50-60d CDBS, IHB, Synphot, WWW reports CDBS CDBS CDBS CDBS TIR mid-to-late mid-cycle ISR ISR, Synphot 1 e-/hr 0.8e-/pix 0.3% 0.3% 0.3% 0.03 mag 1% 1-2% "Internal" Scheduling Required Products Accuracy Required Notes

ID

Proposal Title

10744

WFPC2 Decons & Associated Observations

Decons, phot.monitor, internals, UV throughput, VISFLATS and UVFLATS, darks.

10748 weekly, exc. decon wk continuous continuous 1/cycle 1/cycle 1/cycle 2 19 552 7 4 80 20 50 mid-to-late mid-to-late mid-cycle 44 every 7 days, exc.decon wk

Standard Darks

weekly, exc. decon wk

264

every 7 days, exc.decon wk

CDBS updates and weekly WWW hot pixel lists. BIAS, INTFLATS in F555W for gain and throughput stability measurements F502N only (time dependence only) F300W only Flats in all the filters used in Cycle 14, both gain settings/shutters. Continue CTE monitor. Test for chip dependence. GRW+70D5824 in filter/chip combos used for science in Cycle 14. Placeholder for unexpected items.

Chapter 1: WFPC2 Instrument Handbook Update

10745

Internal Monitor

10749

Visible Earth Flats

10750

UV Earth Flats

10751

Intflat & Visflat Sweeps, Filter Anomaly Check

10746

CTE Monitor

10747

Photometric Monitor

~10% reserve

TOTAL TIME (including all executions)