A list of commands specifying the transforms to be combined. If this parameter begins with "@", then the rest of the parameter value is treated as a filename. The commands will be read from this file one per line.
The following commands are available: trans(dx,dy) - translate by dx horizontally, and dy vertically. rot(angle) rotate counter-clockwise by angle degrees. scale(sx, sy) scale by a factor of sx horizontally, and sy vertically file(filename) read a translation from a FITS file. This file may be the output from another run of this tool or from getxform.
"scale(2,2)" results in a scaling by a factor of two.
"trans(-10.0, -20) rot(30) trans(10, 20)" does a rotation of 30 degrees about the point (10,20).
trans(100, 100) file(raw2sky.xform) trans(-50, -50) Applies windowing to the transform specified in the file raw2sky.xform. The resulting transform will be appropriate for an input image with the first 100 pixels clipped off and an output image with the first 50 pixels clipped off.
The FITS file which will specify the resulting transform
Write HISTORY keywords to output?