Uninstall astrometry-data-tycho2-08-littleendian
To remove just astrometry-data-tycho2-08-littleendian package itself from Debian Unstable (Sid) execute on terminal:
sudo apt-get remove astrometry-data-tycho2-08-littleendian
Uninstall astrometry-data-tycho2-08-littleendian and it's dependent packages
To remove the astrometry-data-tycho2-08-littleendian package and any other dependant package which are no longer needed from Debian Sid.
sudo apt-get remove --auto-remove astrometry-data-tycho2-08-littleendian
Purging astrometry-data-tycho2-08-littleendian
If you also want to delete configuration and/or data files of astrometry-data-tycho2-08-littleendian from Debian Sid then this will work:
sudo apt-get purge astrometry-data-tycho2-08-littleendian
To delete configuration and/or data files of astrometry-data-tycho2-08-littleendian and it's dependencies from Debian Sid then execute:
sudo apt-get purge --auto-remove astrometry-data-tycho2-08-littleendian
See Also
How to remove astrometry-data-tycho2-08-littleendian package from Debian Unstable (Sid)