To uninstall qfitsview just follow these instructions.
sudo apt-get remove qfitsview
This will remove just the qfitsview package itself.
sudo apt-get remove --auto-remove qfitsview
This will remove the qfitsview package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for qfitsview then this will work.
sudo apt-get purge qfitsview
Or similarly, like this qfitsview
sudo apt-get purge --auto-remove qfitsview
|Maintainer||Debian Astro Team <email@example.com>|
|Description||FITS file viewer based on DPUSER two-dimensional images, it also provides means to explore three-dimensional data cubes. It integrates the functionality of DPUSER which can be accessed directly out of QFitsView.|