For the All-Sky Data Release, the 2MASS ID number is the 2MASS declination zone, starting with 0 at the South Pole and moving north 0.1 degree at a time, followed by the sequence number of the star within the RA-sorted zone catalog.
For the Second Incremental Data Release data, the 2MASS ID number is the 2MASS region number, which is not the RA in hours because some one-hour bands have multiple regions, followed by by the sequence number of the star within the region, to fill seven decimal places. The relationship between region number, catalog file, and RA is shown in this table.
Set the environment variable TMC_PATH or the variable tmccd in libwcs/tmcread.c. to the directory containing the region files
To search a rectangular or circular region on the sky, use stmc.
The minimum command line is
imtmc FITS or IRAF filenameThe same effect can be obtained by running
imcat -c tmc FITS or IRAF filename