Now I have been up and running the Pentax 645 300 mm lens. Looks to do well even if it's 35 years old.
When looking on the stars they are a bit distorted, it's even all over the frame. With CCD'Inspector I also have the information that the sensor is tilted.
Have a look here:
http://www.astrofriend.eu/astronomy/...645-300ed.html
What do you think, can the tilt also be the problem of the triangular stars ? Or what cause this kind of distortion of the star profile ?
/Lars