World Coordinate System

The term "World Coordinate System", or "WCS" refers to a coordinate system that describes the positions of objects in the sky rather than in the columns and rows of an image. Mira adopts the WCS definition of the FITS format standard. This standard proscribes both the way in which world coordinates are expressed in the image header and also the image coordinate systems available for FITS format images. Any FITS image meeting the FITS WCS standard will be properly interpreted by Mira. The WCS is implemented using a specific set of header keywords (see "World Coordinate System Keywords" in the Mira User's Guide). The WCS calibration stored in image headers may be used to align them at the subpixel level using the CImCombine:AlignWcs method.

Note	Mira implements FITS WCS support using the dynamic link library FitsWcs.dll. This library resides in the Modules\ subdirectory. If this DLL is not present at startup, Mira will operate normally but will not display world coordinates for FITS images even though they have WCS information.

Related Topics