Astroman
23-05-2005, 08:51 PM
Okay there is alot of talk on pinched secondaries of late and I am interested in finding out how you can test to see if your scope has some form of pinching.
In images of Stars or Planets with bright moons, when focusing on them they produce a coma like image before going into a not quite pin point. Some of this may be caused by the EP's, but I think there may be something else.
Below is an image of my secondary mirror in it's cell, this was before it was alumanised and the cell repainted.
http://www.theastroweb.com/astronomy/telescopes/newscope_sec.jpg
Also the secondary was a little hard to put back into the cell for some reason.
In images of Stars or Planets with bright moons, when focusing on them they produce a coma like image before going into a not quite pin point. Some of this may be caused by the EP's, but I think there may be something else.
Below is an image of my secondary mirror in it's cell, this was before it was alumanised and the cell repainted.
http://www.theastroweb.com/astronomy/telescopes/newscope_sec.jpg
Also the secondary was a little hard to put back into the cell for some reason.