: This is the authoritative source for Two-Line Element (TLE) sets for all cataloged satellites. You can register for a free account at Space-Track to download custom satellite text files.
: Because satellite orbits decay or change, it is recommended to download a fresh version of these files every one to two weeks to maintain accuracy. Download 08ndasat txt
Satellite identification program for astrometrists - Project Pluto : This is the authoritative source for Two-Line