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DssMap - Map points using a Digitised Sky Survey plate solution

Description:
The DssMap class implements a Mapping which transforms between 2-dimensional pixel coordinates and an equatorial sky coordinate system (right ascension and declination) using a Digitised Sky Survey (DSS) astrometric plate solution.

The input coordinates are pixel numbers along the first and second dimensions of an image, where the centre of the first pixel is located at (1,1) and the spacing between pixel centres is unity.

The output coordinates are right ascension and declination in radians. The celestial coordinate system used (FK4, FK5, etc.) is unspecified, and will usually be indicated by appropriate keywords in a FITS header.

Constructor Function:
The DssMap class does not have a constructor function. A DssMap is created only as a by-product of reading a FrameSet (using astRead) from a FitsChan which contains FITS header cards describing a DSS plate solution, and whose Encoding attribute is set to "DSS". The result of such a read, if successful, is a FrameSet whose base and current Frames are related by a DssMap.
Inheritance
The DssMap class inherits from the Mapping class.
Attributes
The DssMap class does not define any new attributes beyond those which are applicable to all Mappings.
Functions
The DssMap class does not define any new functions beyond those which are applicable to all Mappings.


next up previous 264
Next: Ellipse - An elliptical region within a 2-dimensional Frame
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AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
7th December 2012
E-mail:starlink@jiscmail.ac.uk

Copyright (C) 2012 Science \& Technology Facilities Council