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Card - Index of current FITS card in a FitsChan   

Description:
This attribute gives the index of the "current" FITS header card within a FitsChan, the first card having an index of 1. The choice of current card affects the behaviour of routines that access the contents of the FitsChan, such as AST_DELFITS, AST_FINDFITS and AST_PUTFITS.

A value assigned to Card will position the FitsChan at any desired point, so that a particular card within it can be accessed. Alternatively, the value of Card may be enquired in order to determine the current position of a FitsChan.

The default value of Card is 1. This means that clearing this attribute (using AST_CLEAR) effectively "rewinds" the FitsChan, so that the first card is accessed next. If Card is set to a value which exceeds the total number of cards in the FitsChan (as given by its Ncards attribute), it is regarded as pointing at the "end-of-file". In this case, the value returned in response to an enquiry is always one more than the number of cards in the FitsChan.

Type:
Integer.

Class Applicability:
FitsChan
All FitsChans have this attribute.



next up previous
Next: Class - Object class name
Up: AST Attribute Descriptions
Previous: CarLin - Ignore spherical rotations on CAR projections?

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 210
R.F. Warren-Smith & D.S. Berry
30th April 2003
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2003 Central Laboratory of the Research Councils