The following describes the most significant changes which
occurred in the AST library between versions V5.6-1 and V5.7-0:
- The FitsChanFitsChan class support for the IRAF-specific “TNX” projection has
been extended to include reading TNX headers that use a Chebyshev
representation for the distortion polynomial.
- The FitsChan class support for the IRAF-specific “ZPX” projection has
been extended to include reading ZPX headers that use simple or Chebyshev
representation for the distortion polynomial.
- A bug has been fixed in the FitsChan class that caused headers
including the Spitzer “-SIP” distortion code to be read incorrectly if no
inverse polynomial was specified in the header.
- A new attribute called PolyTanPolyTan has been added to the FitsChan class. It
can be used to indicate that FITS headers that specify a TAN projection
should be interpreted according to the “distorted TAN” convention
included in an early draft of FITS-WCS paper II. Such headers are created
by (for instance) the SCAMP tool (http://www.astromatic.net/software/scamp).
- The PolyMapPolyMap class now provides a method called
astPolyTranastPolyTran
that adds an inverse transformation to a PolyMap by sampling the forward
transformation on a regular grid, and then fitting a polynomial function
from the resulting output values to the grid of input values.