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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.
 Copyright (C) 2021 East Asian Observatory
  -  ←Prev 
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 A Library for Handling
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Coordinate Systems
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