New Celestial Coordinates Task - SKYCTRAN


A new task skyctran has been added to the image matching package IMMATCH. Skyctran supports the equatorial (fk4, fk4 [no e terms], fk5, geocentric apparent), ecliptic, galactic, and supergalactic celestial coordinate systems, as well as the iraf mwcs (logical, tv, physical, and world) systems. Skyctran can transform from any one of the supported systems to any other using a user defined or image celestial coordinate system. In interactive mode skyctran can accept image cursor input. Coordinate transformations can be performed in place or new lists of input and output coordinates only can be written. Typical skyctran applications include precessing coordinate lists, transforming from fk4 to fk5 coordinates and vice versa, transforming from equatorial to galactic coordinates and vice versa, locating objects found in one image with a known wcs in another image with a known wcs, and computing matched pixel coordinate grids for images with known wcs for input to the registration tasks geomap and geotran.

Skyctran uses the iraf imio and mwcs libraries to attach celestial coordinate values to the image pixels and the Starlink positional astronomy library slalib to perform any required celestial coordinate transformations. Slalib has been made available to the iraf project courtesy of Patrick Wallace of Starlink, and will be distributed as part of the iraf core system math package in future releases of iraf.

Skyctran is available as part of the external add-on package IMMATCH. To retrieve and install immatch, follow the installation instructions found in the readme file.


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Last updated: 12December1995