I have a very good condition Pentax 67 SMC 300mm F4 lens.
These Pentax lenses are good choices for astrophotography because they have around 86mm backfocus, the most of any brand of lens.
This one is great for narrowband. You can use it for normal imaging with a bit of chromatic aberration correction in post processing or stop it down a bit.
A great way to start into astrophotography cheaply and easily. There are plenty of adapters on Ebay that are also cheap.
$250 + $15 postage.
Greg.
Last edited by gregbradley; 16-12-2020 at 06:25 PM.
$200 + $15 postage. Its a medium format lens with 86mm backfocus. Adapters are plentiful and cheap on ebay. You can use it with Canon Nikon Sony Fuji etc.