This procedure is an extenion of (and a wrapper for) the xyad program in the astronomy user's library. It converts (x,y,z) pixel coordinates to (a,d,v) sky / velocity coordinates for a 3D data cube, based on the fits header.
This procedure calls extast3 from the Beaumont IDL library and xyad from the IDL Astronomy User's Library.
- head in required
A fits header. String array
- x in required
x pixel coordinates. scalar or vector
- y in required
y pixel coordinates. scalar or vector
- z in required
z pixel coordinates. scalar or vector
- ortho in optional
Set this keyword if the third axis of the input coordinates is orthogonal to the first two; that is, if xyz describe a cube, and x and y are the same for each slice. When this is true, the computation can be performed more quickly.
March 2010: Written by Chris Beaumont May 2010: Fixed a bug in the call to xy2ad. cnb. June 2011: Optimized for case when x,y,z describe a cube, with (x,y) constant along z slices.
|Modifcation date:||Tue Jun 7 11:00:02 2011|