Can't reach focus with a 2" mirror diagonal.
Posted 23 September 2003 - 11:26 AM
I now have a very high contrast, tack sharp, image and chromatic aberration is almost invisable. You have to look really hard to find any! This is what I was after; to push this design to it's theoretical limits. Now, I would dare to put this "project" scope up against anything in it's class and nearly identical to high quality semi-APOs.......but!?
Using my Panoptic and Nagler 6 lenses, I can reach focus with a Lumicon 1.25 mirror diagonal but not with a Meade 2" mirror diagonal.
Assuming the draw tube starts out fully retracted, the 1.25 mirror requires about 2 1/2" of back travel to achieve focus but the draw tube won't travel "in" far enough to achieve focus with the Meade 2" mirror.
With the draw tube fully retracted, the distance from the objective lens to the centers of each mirror size seems to be equal. I'm confused!
Anybody have any ideas about what is going on here and how to fix it?
Posted 23 September 2003 - 12:50 PM
if it indeed is, why don't you just chop off an inch or so off the back & remount the focuser?
Posted 23 September 2003 - 01:29 PM
Hope this helps,
Posted 23 September 2003 - 01:53 PM
I must admit that I haven't tried my 2" eyepieces yet. The fog rolled in before I had a chance to test them.
The low profile 1.25 eyepiece adaptor sounds like a viable option to try, "before" I cut the optical tube!
To cut my tube, I'd also have to move my finder (2) mounts that are bolted into place, not to mention, plugging the old holes...and...geting the tube cut straight.
Guess I'll search for an adpator.