Astrometry.net Tycho-2 little endian index files (22'-30')

 The astrometry engine will take any image and return the astrometry
 world coordinate system (WCS), a standards-based description of the
 transformation between image coordinates and sky coordinates.
 .
 This package contains the 4107 index file from the Tycho-2 catalog
 containing skymarks of sizes 22 arcminutes to 30 arcminutes. Byte order
 is litte endian.