ccmap - Compute image plate solutions using celestial coordinate lists cctran - Transform from x-y to ra-dec and vice versa using plate solutions ccsetwcs - Create an image wcs from the plate solution ccxymatch - Match celestial and pixel coordinate lists using various methods geomap - Compute geometric transforms using matched coordinate lists geotran - Transform 1-D or 2-D images using the computed transforms geoxytran - Transform coordinate lists using the computed transforms imctran - Transform from one image celestial wcs to another linmatch - Match the linear intensity scales of 1-D or 2-D images linxymatch - Match pixel coordinate lists using various methods psfmatch - Match the point-spread functions of 1-D or 2-D images slalib - Starlink positional astronomy library skyctran - Transform coordinate lists from one celestial wcs to another skymap - Compute geometric transforms using image celestial wcs information skyxymatch - Generate matched x-y lists using image celestial wcs information sregister - Register 1-D or 2-D images using image celestial wcs information wcscopy - Copy the wcs of one image to that of another wcsctran - Transform image coordinates from one builtin image wcs to another wcsmap - Compute geometric transforms using image wcs information wcsxymatch - Generate matched x-y lists using image wcs information wregister - Register 1-D or 2-D images using image wcs information xregister - Register 1-D or 2-D images using x-correlation techniques
The ccmap, cctran, ccsetwcs, geoxytran, imctran, linmatch, linxymatch, psfmatch, skyctran, skymap, skyxymatch, sregister, wcscopy, wcsmap, wcsctran, wregister, and wcsxymatch tasks are new. Geomap and geotran are slightly modified versions of the corresponding tasks in the images packages. These modifications were necessary to properly support the new registration tasks. Xregister is already available under 2.10.3/2.10.4 and in the nmisc external package but was included here for completeness. Immatch is still under development and new tasks will be added in the future.
The major new capabilities of the package are ability to: 1) compute the wcs for an image given a matched list of pixel and celestial coordinates and store the wcs in the image header, 2) register images using accurate world coordinate information in the image headers, 3) match the image point-spread functions by computing the kernel required to convolve the higher resolution image to the resolution of the lower resolution image, 4) match the linear intensity scales of images using a variety of techniques including pixel-to-pixel comparisons and statistical measurements in one or more regions, and 5) perform celestial coordinate transformations on coordinate lists.
Some of this work was done in collaboration with Drew Phillips and is summarized in the article "Registering, PSF-Matching and Intensity-Matching Images in IRAF" (A.C. Phillips and L.E. Davis 1995, in Astronomical Data Analysis Software and Systems IV ASP Conference Series Vol. 77, eds. R.A. Shaw, H.E.Payne and J.J.E Hayes, p 297)
All the celestial coordinate transformations required by the ccmap, imctran, skyctran, skyxymatch, skymap, and sregister tasks are performed by routines in the Starlink positional astronomy library Slalib. Slalib has been made available to the IRAF project courtesy of Patrick Wallace of Starlink, and will become part of the iraf core system math package in the next major release of iraf.
These tasks are being made available prior to distribution as part of the IRAF 2.11 core system in order to invite user testing and comments. Please send any questions, comments, or problem reports to firstname.lastname@example.org or email@example.com. The package retrieval and installation instructions are available in the readme file.
Last updated: 17May1996