Hi Pete,
Good, then I'm not alone with this lens :-)
I know this lens will not perform very well when it come to sharpness. But It had been fun to do some test and see how it perform in other aspects. I did that many years ago but didn't have full control of the details then.
Tonight my plan was to do some Moon shots. But direct I get in trouble, I can't past focus at infinity. It looks that I'm almost on spot at the infinity stop. It looks very complicated to adjust the infinity stop at this lens. Another solution is to shorten the adapter, but don't have the machines to do that.
Anyway I shall spend a night on some object to have more test photos even if the focus is not perfect, maybe the lens shrinks out in the cold :-)
By the way, I updated my test page:
http://www.astrofriend.eu/astronomy/...vs-pentax.html
There is another problem with a lens like this. Now when I have start using the smartphone app to control my camera and lens. I can adjust the focus without touching the lens or camera, no vibration! Tonight when I try to focus manuell on Moon with the Pentax lens it cause a lot of vibration and make the focus process difficult.
Ps.
Your astrophotos at astrobin looks very good!
/Lars