... In the above example, the second region uses the global coordinate system (PHYSICAL by default). ... Supported systems include: name description ---- ----------- PHYSICAL pixel coords of original file using LTM/LTV IMAGE pixel coords of current file FK4, B1950 sky coordinate systems FK5, J2000 sky coordinate systems GALACTIC sky coordinate systems ECLIPTIC sky coordinate systems ICRS currently same as J2000 LINEAR linear wcs as defined in file In addition, two mosaic coordinate ...

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• Image Display
• Quick Look Tools
• Coordinate Systems

Data access in GIPSY is done through a set of routines collectively known under the name `` GDS '' (GIPSY Data System). ... A set consists of one or two files: the descriptor file and the image file. ... In GIPSY there are kinds of coordinates: . ... To retrieve a descriptor item, given its name and level, the GDS reading routines start looking at the specified level and if it is not found there, higher levels are tried. ... Every GDS routine has an integer error argument, which often is optional. ...

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• World Coordinate Systems (WCS) in FITS
• Image Items
• Region of Interest and Pixel Blanking

... The initial descriptions of the FITS format provided a simplified method for describing the physical coordinate values of the image pixels, but deliberately did not specify any of the detailed conventions required to convey the complexities of actual image projections. ... They were CRPIX n for the reference pixel location on pixel axis n , CRVAL n for the coordinate value at that pixel, CDELT n for the increment at that pixel in the coordinate value, and CTYPE n for the type of coordinate. ...

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• New Developments in the FITSIO and Fv Software Packages
• ZGSC (Compressed GSC) and XSKYMAP
• ASC Coordinate Transformation-The Pixlib Library

... Image formation is typically described as a linear process. ... where, for 2-dimensional systems, the object coordinates are and the image coordinates are . Such a general description of a linear system is termed shift-variant, because the shape of , the impulse response (or point spread function, PSF), might change as the object position, , is shifted. ... Hence, the exit pupil geometry changes with field position, so the system response changes with field position (i.e., is shift-variant). ...

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• Generic Targets List [Generic_Targets]
• Introduction to HST Data Handbook v8.0
• McNown Hunt: Approximate Shift-Invariance

... The described algorithm is suitable for measurements of complex images of stars. ... a) the zero-based number of stars in the complex (multicentric) image, . b) set of preliminary coordinates - x i , y i , for all stars, index i is number of a star, . ... i - index of a star in the complex image; . ... These parameters are calculated by a nonlinear method of a least squares.The main output parameters of this algorithm are x i , y i ; where the index i is number of a star in the multicentric image. ...

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... The European HST Archive has been moved to ESA's European Space Astronomy Centre ( ESAC ), Spain, where most of ESA's Space Science Archives are located and operated from. ... The Space Telescope European Coordinating Facility (ST-ECF), jointly operated by ESA and the European Southern Observatory ( ESO ) was, until the end of 2010, the European HST science facility, supporting the European astronomy community in exploiting the research opportunities provided by the Hubble Space Telescope. ...

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... The system is based on two straight lines ("axes"), perpendicular to each other, each of them marked with the distances from the point where they meet ("origin")--distances to the right of the origin and above it, the origin being taken as positive and on the other sides as negative (see drawing below). ... One system (" polar coordinates ") uses the length r of the line OP from the origin to P (i. e. the distance of P distance to the origin) and the angle that line makes with the x-axis. ...

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• Trigonometry beyond 90 degrees
• Parallax

... In making a background map or exposure map in sky coordinates it is useful to be able to transform a CCD image of a particular quantity into these sky coordinates. ... This should contain WCS keywords to define the sky projection plane and the image pixel size; the image array itself supplies the numbers of pixels in the image X and Y directions. ... Also, the template image need not be from the same instrument as the chip images, or even an XMM image at all. ...

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• SciSim development releases

... Tonight's Sky . ... Observing . ... Sky this Month . ... Gravitational wave search provides insights into galaxy evolution and mergers . ... space flight . ... Astronomy for Kids . ... NASA describes Hubble fix . NASA confirms new Hubble Space Telescope servicing mission details. ... Hubble fix a "go" . ... Only registered members of Astronomy.com are allowed to comment on this article. ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. ...

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• Comet construction | Astronomy.com
• A meeting with a comet | Astronomy.com
• Web Extra: 25 asteroids to spot through binoculars | Astronomy.com

Each Apache module is described using a common format that looks like this: . Status: status . ... This indicates how tightly bound into the Apache Web server the module is; in other words, you may need to recompile the server in order to gain access to the module and its functionality. ... A module with "Extension" status is not normally compiled and loaded into the server. ... Modules which are not included with the base Apache distribution ("third-party modules") may use the "External" status. ...

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• Definitions of terms used to describe Apache directives

Modules | ... Apache HTTP Server Version 2.2 . Apache > HTTP Server > Documentation > Version 2.2 . ... This document describes the terms that are used to describe each Apache module . ... This indicates how tightly bound into the Apache Web server the module is; in other words, you may need to recompile the server in order to gain access to the module and its functionality. ... Modules which are not included with the base Apache distribution ("third-party modules") may use the "External" status. ...

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• Terms Used to Describe Directives - Apache HTTP Server
• HwB: Cable Tutorial (Offline)
• HwB: Adapter Tutorial (Offline)

Modules | ... Apache HTTP Server Version 2.2 . Apache > HTTP Server > Documentation > Version 2.2 . ... This document describes the terms that are used to describe each Apache module . ... This indicates how tightly bound into the Apache Web server the module is; in other words, you may need to recompile the server in order to gain access to the module and its functionality. ... Modules which are not included with the base Apache distribution ("third-party modules") may use the "External" status. ...

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• Space-Time Diagrams
• Terms Used to Describe Directives - Apache HTTP Server
• ESO-MIDAS Users Guide Overview

... In polar coordinates, the point P is defined by its distance r from the origin O (see drawing) and by its polar angle ("azimuth" on a map) between the x-axis and the "radius" r = OA, measured counter-clockwise. ... When one or both are negative , the angle f is larger than 90 degrees, and such angles never appears in any right-angled triangle. ... There is a simple solution , though: use the above equations to re-define sin f and cos f for such larger angles! ... But it also works for larger angles....

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For the frequency-agile upgraded Arecibo Telescope, there are bands where Radio Astronomy has either no regulatory protection, only a "secondary" status or, at best, a "shared-primary" status. In these bands, observations can only be carried out either by utilizing RFI-excision techniques or in coordination with other users. This will open a page from the March 98 issue of the NAIC/AO Newsletter that describes the current measures taken to avoid RFI in the new wide-band L-band receiver. ...

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• ALFAZOA Data Release
• radar
• Rotang - IDL procedure for calculating the optimum rotation angle for ALFA

The Network Time Protocol (NTP) is used to synchronize the time of a computer client or server to another server or reference time source, such as a radio or satellite receiver or modem. ... Information on the NTP architecture, protocol and algorithms can be found in the following articles and reports, which are available online . Mills, D.L. Internet time synchronization: the Network Time Protocol. ... Mills, D.L. Network Time Protocol (Version 3) specification, implementation and analysis. ...

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• APOD: 2000 January 8 - Albert Einstein Describes Space and Time
• APOD: September 27, 1998 - Albert Einstein Describes Space and Time
• Pulse-per-second (PPS) Signal Interfacing

Stellarium 0.12.3 . ... Classes . ... Pulsar Class Reference . ... Pulsar (const QVariantMap &map) . ... Get a QVariantMap which describes the pulsar. ... getSelectPriority (const StelCore *core) const . ... getInfoString (const StelCore *core, const InfoStringGroup &flags) const . ... getVMagnitude (const StelCore *core, bool withExtinction=false) const . ... getAngularSize (const StelCore *core) const . ... getPositionInfoString (const StelCore *core, const InfoStringGroup &flags) const . ... core . ...

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• Stellarium: Supernova Class Reference
• Stellarium: Quasar Class Reference
• Stellarium: Exoplanet Class Reference

Astronomy Picture of the Day . ... 8.01.2000 . ... Explanation: Albert Einstein (1879-1955) is considered by many the greatest astrophysicist and single most significant Person of the 20th Century . ... One reason Einstein was awarded the 1921 Nobel Prize in Physics was to make the prize more prestigious. ... NASA Web Site Statements, Warnings, and Disclaimers . ... Publications with keywords: scientist - time - century - space . Publications with words: scientist - time - century - space . ...

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• Астронет > Albert Einstein Describes Space and Time

. Parent Directory . 00-index . dwpdde.zip

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• Notation

... There is an opportunity to perform O-C calculations for objects which are absent in the data base of the package. Such objects can be described by orbital elements or by initial coordinates and velocities. ... On pressing Edit file button user has a possibility to look through the list of object elements or their coordinates and velocities to add or to change it. ... For example, the designations of objects in the list can occupy the last position in each line. ...

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• IAA EOP Service

... My mother had a 'star named for me' with the International Star Registry (henceforth ISR) as a gift for this Christmas. ... On the back of the chart, a sticker described the precise location and visual magnitude of the star, taken from the Hubble Guide Star Catalog. The first thing I noticed, was the chart was Epoch 1950. ... The coordinates were also exactly those on the ISR sticker, so I now knew that even though the ISR chart was epoch 1950, the coordinates on the sticker were epoch 1983. ...

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