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Mounting an Orion dob OTA onto a CG-5

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#1 acav2488

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Posted 07 January 2010 - 02:21 PM

Hello all,
I was wondering if anyone has any ideas or has had any experiences with mounting an orion skyquest XT6 on a CG-5 mount. Ive looked at the tube rings from orion and since they suggest the 182mm rings for a 6 inch scope i figure those would work? Also, do the dovetail plates from orion fit on the celestron mount? Any feedback would be much appreciated. Thanks!

-Also, I ultimately would like to be able to piggyback my Nikon D40 on the XT6. From what I have read about the CG-5, the 13.5 lb OTA shouldn't be too much weight to get some fairly accurate tracking. If anyone has any thoughts on this please fill me!

#2 coopman

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Posted 08 January 2010 - 07:29 PM

You'll need to have some easy way of rotating the tube or you're going to be required to contort into some really back-breaking positions with a Newt on a GEM.

#3 Doug76

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Posted 08 January 2010 - 10:14 PM

The weight of the XT6 is fine for the mount, but the length may make it a bit shaky in the wind.
Any Vixen type dove tail bar, including Orion's, fit the CG-5.
For visual, you'll have to get used to rotating the OTA in the rings to keep the eyepiece where you can look into it.
For AP, this is a non-issue.

#4 guyroch

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Posted 09 January 2010 - 01:10 AM

I've looked at the tube rings from orion and since they suggest the 182mm rings for a 6 inch scope i figure those would work?


A 6 inch scope is equal to 150mm, so I'm not sure about the 182mm rings. It seems odd that they say 182mm rings will fit a 150mm OTA. :question:

#5 jwaldo

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Posted 09 January 2010 - 01:51 AM

I've looked at the tube rings from orion and since they suggest the 182mm rings for a 6 inch scope i figure those would work?


A 6 inch scope is equal to 150mm, so I'm not sure about the 182mm rings. It seems odd that they say 182mm rings will fit a 150mm OTA. :question:


I just picked up the 182mm rings for my 6" newt, and they were the right size (actually, they were about 2mm too big, but that's probably because my OTA isn't from Orion). There's quite a bit of space between the mirror edge and the tube.

#6 acav2488

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Posted 09 January 2010 - 09:59 AM

Hey thanks for the replies. Clay and Doug I'm glad you mentioned that tip about turning the scope to keep the eyepiece in a convenient, you definetly answered a question that i would be asking in the future. And yeah I was certainly curious about how the length of the tube was going to affect my setup and as long as wind is going to be my biggest problem then I'm ok that. As far as the Orion tube rings go, on their website they do suggest the 182mm(which is a little over 7 inches) rings for their 6 inch scopes. It says to use felt to fill in any space for a ring that doesn't fit tightly. But before I order the rings I need to find out how long the dovetail plate should be? as Doug mentioned, it's a long tube (about 45.5 inches) so is a 13 inch plate long enough?

#7 Doug76

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Posted 09 January 2010 - 01:18 PM

I've looked at the tube rings from orion and since they suggest the 182mm rings for a 6 inch scope i figure those would work?


A 6 inch scope is equal to 150mm, so I'm not sure about the 182mm rings. It seems odd that they say 182mm rings will fit a 150mm OTA. :question:


Unlike refractors, reflectors are made with a bigger tube than the objective size. This allows room for mounting the mirror cell, and most importantly providing space to lower the effect of tube currents, which tend to be at their worst right along the tube wall.

#8 Luigi

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Posted 09 January 2010 - 01:50 PM

Long Vixen style dovetails are very flexy, much more so than the scope tube. Keep the rings close together and the dovetail short for max stiffness.

#9 Doug76

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Posted 09 January 2010 - 03:27 PM

Agreed, unless you get one of the solid machined type. They are quite expensive though.

#10 acav2488

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Posted 09 January 2010 - 05:12 PM

So would an 8 inch dovetail plate be a better idea?

#11 Doug76

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Posted 09 January 2010 - 05:21 PM

8" isn't too long, and would keep with the good advice Luigi offered.

#12 jwaldo

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Posted 09 January 2010 - 05:36 PM

So would an 8 inch dovetail plate be a better idea?


I'm using the 8" dovetail with my setup. It seems sturdy enough. The whole setup is sturdier than I'd expected; vibrations stop after a second or two :jump:

#13 acav2488

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Posted 10 January 2010 - 12:28 AM

well hey thanks everyone..within the week I should have my cg-5 plus the tube rings for my scope which will give me what I need for some great observing sessions as well as what I need to take my first real astrophotos....thanks for all the feedback! I'll let you know how it turns out.

#14 DCJimT

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Posted 13 September 2012 - 11:46 AM

Alex, how did the project turn out? I'm thinking about setting up my XT6 OTA for use on the CG-5, too, and would appreciate any insight. Did your setup allow the OTA to continue using the dob mount?

#15 AlBoning

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Posted 13 September 2012 - 03:00 PM

I recently converted an Apertura AD8 (8" f/5.9) to EQ mounting, in this case to an Atlas. Details about this and modifications done can be found here ...

http://www.telescope...osts=19&start=1

I have a certain fondness for 6" f/8 newts, I often think about about them, and I'd have one if it didn't represent a duplication of equipment.

But just two nights ago I was observing and thinking the eyepiece height of the AD8 on the Atlas was about right for me and my observing chair ... but I found myself wondering if a 6" f/8 might prove to be just a little too high. I also began to wonder if there would be enough clearance between the tripod legs and the OTA when observing/slewing near zenith. I think it would work out okay but it is something to consider, at least briefly.

As regards the payload weight of the scope I'm reminded of the experience I had with the SkyViewPro 8 EQ. The bare OTA is 16.5 lb but once I added the tube rings, Wilcox rings, dovetail mounting bar, 9x50 RACI, another dovetail shoe, FlockBoard, a grenade sized eyepiece, and a fan, the in the saddle weight had grown to 27 lb. Now I didn't know this it first, and the SVP (rated for 20 lb) handled it without a squawk, but one day I weighed the OTA, and with another, and heavier, scope already contemplated I ordered the Atlas.

#16 oldstargazer

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Posted 13 September 2012 - 09:56 PM

I have my 10 inch orion dob mounted on my CG-5gta with a 16 inch long solid bar dovetail and it has given me my best images of jupiter using neximage. Only drawback to this setup is that it won't let me get my DSLR close enough to the mirror to get it into focus. But I finally solved that issue by getting a C11.






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