Replacing Celestron's Finderscopes
Posted 23 June 2022 - 09:10 PM
I think the Celestron straight through finderscope isn't very conducive to tracking the ISS, for example. It doesn't protrude past the end of the back of the OTA and feels uncomfortable to **** my head to get a good view. Is this anyone else's experience? If so, how did you deal with it?
Posted 23 June 2022 - 09:26 PM
I think the Celestron straight through finderscope isn't very conducive to tracking the ISS, for example. It doesn't protrude past the end of the back of the OTA and feels uncomfortable to **** my head to get a good view.
IMHO the backend of an SCT always was a lousy place to put the finderscope, ergonomically.
I understand why they did that - they needed something thick to drill & tap which only leaves the front or back cells, and were too mean to do any better.
They way they mount it is a PITA. But if it extends behind the back of the scope it often blocks your head when you want to look in the eyepiece, worse.
When I used my rig altaz I found that having the finderscope on a rail well clear of the OTA and slightly forward of the altitude axis was ideal - it means the height of the finder eyepiece doesn't change much, though its better if it does rise a little with increasing elevation as you have to tilt your head up (see photo below).
With an altaz fork-mounted SCT this is approximated by bolting the finder on one side of the corrector cell.
Another way is to add say an ADM MDS rail and mount the finder on that, slightly forward of the fork.
If you're equatorial however all bets are off - the finder will be a pain whatever you do. For this reason when I moved to a Losmandy G11 mount (equatorial only) I have added encoders and Nexus II so that I now have push-to positioning accurate to an arc minute or two - easily centres objects in the big mak without using a finderscope at all.
The other ways to ditch the finderscope and use something with a camera that plate-solves.
Edited by luxo II, 23 June 2022 - 09:34 PM.
Posted 23 June 2022 - 09:27 PM
Depending what scope I am using I have a dot finder which is almost always my go to. Then a straight thru 50 mm finder. Then I have a right angle finder if I am using my newt or I am in a difficult position.