[Dennis]

Originally Posted by AstroViking

I suspect it might not be an image file... I'm downloading it now to have a look at for you.

I found a copy of the file here https://www.sdss4.org/dr17/algorithms/qso_catalog/ for anyone else who's curious.

FWIW, the file is about 2.4GBytes in size, so not to be sneezed at.

Cheers,
V

Thanks Steve, I should have warned you about the file size.

I think the file structure may be in a Table format, hence my Image Format apps will not open it.

Cheers

Dennis