90 deg. finder

asimov (John) · #1 03-09-2005, 09:50 PM

Sick of breaking my neck to get to the finder on the refractor at zenith so I came up with this quick mod.

When I purchased my refractor awhile back, I received a 1.25" star diagonal with it. One look thru it on the refractor was enough to put it back in it's box & stow it & buy a decent 2" one. Today I un-boxed it & fitted it to the straight-thru finder. Luckily it slid straight over the finder EP snugly & won't fall off when the scope is pointed at zenith. I slid it on until the finder EP touched the mirror. I unscrewed the chrome sleeve to get my eye closer to the 45 deg mirror. I can rotate the diagonal on the finder axis to any position.

The only draw-back is it halves the FOV..making it sometimes hard to find objects. It's also an aquired thing to get used to a 90 deg finder.

The whole capped chrome sleeve is screwed back on after use as the dust cap.

davidpretorius · #2 03-09-2005, 10:19 PM

nice work!

ving (David) · #3 05-09-2005, 09:58 AM

if you were to take the lens out of the finder and shove an EP in the diagonal it wouldnt work would it?

asimov (John) · #4 05-09-2005, 05:05 PM

No ving, it upsets the focal length of the finder. The only thing you can do if one must go that way, is you gotta cut the main tube & make it shorter to compensate.

The best idea is just to buy a 90 deg finder I guess, but I just wanted to try this to see what happened. I'm getting used to it slowly. It can be a pain cos' of the small FOV but if all else fails I just take it off & use it straight thru to quickly locate the object, bang it roughly in the FOV then slip the diagonal back on.