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Installing Dovetail Bar on Evolution 8" OTA

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#1 jjhart827

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Posted 20 March 2017 - 09:39 PM

So, I just received my new CGEM DX mount that I am eager to use with my Evolution 8" OTA. To that end, I also purchased the Celestron D-Style Dovetail bar (I think this used to be call the CG-5 dovetail bar. It is the anodized orange bar that Celestron sells for 8" OTAs). 

 

At any rate, I can't seem to figure out how to install the dovetail bar on my OTA. The bar came with three thumbscrews that are too long to mount the dovetail securely to the OTA, and the three screws that I had to remove from the OTA to place the dovetail in the correct spot are far too short to be used for installing the dovetail. I'm at a complete loss.

 

What am I doing wrong? Any thoughts? 

 

Clear skies.

 

 



#2 leveye

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Posted 20 March 2017 - 09:56 PM

Use longer screws? I've even had to custom cut the lengths sometimes.



#3 jjhart827

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Posted 20 March 2017 - 10:04 PM

Use longer screws? I've even had to custom cut the lengths sometimes.

But doesn't that seem odd for a Celestron dovetail that is made specifically for this Celestron OTA to come with hardware that doesn't work?



#4 jallbery

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Posted 21 March 2017 - 12:43 AM

The cg5 is the vixen dovetail.  The cge is the "D" style.

 

Rather than replacing the dovetail, i would either replace the saddle (to a dual) or buy an adapter like https://www.amazon.c...r/dp/B003D3LYAQ

 

Why give up using the Evo for visual?



#5 lenrabinowitz

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Posted 21 March 2017 - 05:06 AM

Are you sure you are putting it on the right part of the optical tube?


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#6 junomike

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Posted 21 March 2017 - 03:12 PM

See the first pic here and the forth pic here for proper Dovetail orientation.

 

Mike



#7 jjhart827

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Posted 21 March 2017 - 07:47 PM

OTA Zoom.JPG

See the first pic here and the forth pic here for proper Dovetail orientation.

 

Mike

Actually, it would appear that the proper dovetail location on the Evo 8 is on the "side" of the OTA, across from the Vixen/CG-5 dovetail that comes pre-installed on the tube (for use with the Evo mount). It works out rather well, as when the OTA is installed on the DX mount, the old vixen dovetail sits directly atop to OTA, situated perfectly for a guidescope or other accessories. 

 

 



#8 xHarry

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Posted Today, 02:57 AM

jjhart827: Actually, it would appear that the proper dovetail location on the Evo 8 is on the "side" of the OTA, across from the Vixen/CG-5 dovetail that comes pre-installed on the tube (for use with the Evo mount). It works out rather well, as when the OTA is installed on the DX mount, the old vixen dovetail sits directly atop to OTA, situated perfectly for a guidescope or other accessories.

 

That's one of the things I'm considering - I just got the same mount and have the same scope. How did you manage with the screws?

 

Harry



#9 carver2011

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Posted Today, 11:02 AM

There are no screw holes for a dovetail bar on the sides of the optical tube. There are screw holes for a rail on the opposite side of the tube 180 degrees from the factory installed rail. The other holes to the sides of the present rail position are for accessories. 



#10 jjhart827

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Posted Today, 08:23 PM

There are no screw holes for a dovetail bar on the sides of the optical tube. There are screw holes for a rail on the opposite side of the tube 180 degrees from the factory installed rail. The other holes to the sides of the present rail position are for accessories. 

Depends on what your definition of the "side" is. -- On the Evolution mount, there is a single vixen-style saddle that attaches to the side of the OTA. On the opposite "side", (i.e.: 180 degrees away), is where I installed the Losmandy-style plate. Of course, when you move the OTA from a single-fork Alt-Az mount to an EQ mount, the OTA must be rotated 90 degrees -- which means that the "sides" are now the top and bottom. 



#11 jjhart827

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Posted Today, 08:34 PM

 

 

That's one of the things I'm considering - I just got the same mount and have the same scope. How did you manage with the screws?

 

Harry

Hi Harry, 

 

Actually, I ended up using some screws that happened to come with some other gear I already had. However, I did a little bit of primary research at a local home improvement store and was able to determine that one of the two different sizes of screws needed is 10-24 x 5/8". I didn't take the other size with me, as I had already identified some screws that worked. 

 

Most large hardware and/or home improvement stores have test sockets for different sizes/threads of screws. Just take the screws that you'll need to remove from the OTA housing to your local hardware store, and find out what size threads are on them. Then, you may need to buy screws of that thread type of varying lengths, and see which works best. 




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