iraf.net

Hi David,In V2.10 there was a great deal of work done on maintaining the coordinate
systems through various image transformations. Thus, when you rotate an
image it will keep track of the original coordinates. For many image
transformations such as shifts, block averages, image sections subsequent
programs will properly make use of this information. However, for
operations, such as ROTATE, which end up coupling the image axes some
programs are not prepared to deal with this (they assume the axes are
independent). This is the case with the ONEDSPEC package. The solution in
this case is to reset the coordinate system. The task that does this is
WCSRESET.It was not clear if you did the rotation on a raw image which was not
wavelength calibrated or a wavelength calibrated image. In both cases you
should reset the "physical" coordinate system. If there are wavelengths
this will introduce an error in the wavelengths. You can reset the "world"
coordinate system and then recalibrate the wavelengths, live with the error
(a .2 of a degree rotation may not be significant), or forgo use of SPLOT
or other ONEDSPEC tasks. Note that you can plot the rotated image in
wavelength using IMPLOT or GRAPH and get wavelengths printed with LISTPIX
by specifying that the wcs you want is "world" (the default in these tasks
is "logical" which is the array pixel coordinates).If you have further questions feel free to ask.Yours,
Frank Valdes