How to mount an additional finder scope?

Discussion and instructions for astronomy-related projects
owenh10
Posts: 32
Joined: Mon Feb 27, 2012 10:59 pm

How to mount an additional finder scope?

Unread post by owenh10 » Tue Sep 20, 2016 7:29 pm

I just went out and bought the following items from Amazon:

https://www.amazon.com/gp/product/B005L ... UTF8&psc=1
https://www.amazon.com/gp/product/B0000 ... UTF8&psc=1

(it's an Orion 7020 Illuminated Finderscope and mounting bracket.)

I plan to attach these to my Criterion RV-6 reflector (I've brought this to the Pardon Gray outreaches a couple of times) to use as a Finder's helper and assist when scope is at the zenith, etc. I figure to drill mounting holes in the tube for the plate.

Here's my questions: The original Criterion finder scope is mounted about 45 degrees to the left of the eyepiece hole. Should I mount this 45 degrees to the right? Or should it be opposite (180 degrees) the original finder for better balance? Or is this finder way too big for this scope and I should return it? Or would I be able to place counterbalancing weights on the tube as well?

Since this involves drilling holes in the tube, I don't want to muck it up, so any and all advice would be welcome. Amazon has a generous return policy, so don't be afraid to tell me I made a mistake.

Thanks!

-Owen
Bruce D
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Joined: Sat Jun 14, 2003 6:10 am

Re: How to mount an additional finder scope?

Unread post by Bruce D » Tue Sep 20, 2016 11:00 pm

Hi Owen, if amazon is good about returns you might want to check out the Celestron illuminated RA finder

https://www.bhphotovideo.com/c/product/ ... scope.html#!

$100 at B&H and it looks like it includes the dovetail bracket so you'll save almost $60-
Bruce D
Bruce D
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Joined: Sat Jun 14, 2003 6:10 am

Re: How to mount an additional finder scope?

Unread post by Bruce D » Tue Sep 20, 2016 11:07 pm

What type of mount is the scope on? If it's an equatorial mount it seems there are always going to be times when the finder (and EP) are in awkward positions unless you use one of the schemes to rotate the tube in the rings.

I'm wondering why keep the original finder mounted at all? You can take it off and put the new finder in the same spot- probably using at least one of the existing holes and cutting your chances of making a mistake in half :^)
Bruce D
owenh10
Posts: 32
Joined: Mon Feb 27, 2012 10:59 pm

Re: How to mount an additional finder scope?

Unread post by owenh10 » Wed Sep 21, 2016 5:42 am

Hi Bruce:

Thanks for the responses. I'd like to keep the old finder as I'm use to sighting objects straight through the tube axis while this new one is a right angle. But maybe I will try swapping it out and see how it does.

-Owen
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Pete
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Re: How to mount an additional finder scope?

Unread post by Pete » Wed Sep 21, 2016 10:53 am

Hi Owen,

I too have a Criterion RV-6 donated to my teaching effort by club member Bob Morse. The original drive worked but was very heavy and large and required a 120 VAC outlet, so about 5 years ago the scope was refurbished, recoated, and mounted in a homemade DOB base. The scope sports a Telrad finder as my long experience has been one of confusion whenever trying to find an object in a small, inverted or mirrored type finder. Yes, it's a real pain locating objects near zenith, but on the DOB mount it's a real pain anyway. And just using a 30mm eyepiece provides a pretty decent FOV

The 5° FOV in your Celestron finder scope might prove limiting. But if you're on the original Criterion drive it might be helpful occasionally. At least it's not inverted or mirrored.

Pete
Pete P.
owenh10
Posts: 32
Joined: Mon Feb 27, 2012 10:59 pm

Re: How to mount an additional finder scope?

Unread post by owenh10 » Wed Sep 21, 2016 4:16 pm

Hi Pete:

I've become used to using an inverted finder, (using the both eyes open, merge into one star method), so it might be a more difficult switch for me to use a normalized one . I had considered the Telrad, along with an Orion red-dot finder, and decided on trying out the illuminated reticle finder. That damn Ring Nebula is always straight up in the summer time. :) If a finder scope had both straight through and 90 degree sights, I'd buy it in a heartbeat. That, and a good photographer vest that holds eyepieces rather than lenses.

I do use the original mount, and just replaced recently the cork in the clutch for the drive. Yes, it's heavy, but it dampens wind and vibrations pretty good. I may just attach the new finder, and if I find it's too cumbersome, I'll return the scope and keep the separate mount plate to keep the holes covered.

Hope the skies clear up for a night or two so I can size up the capabilities of this finder before the return date limit runs out.

-Owen
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