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Mounting Guidescope on Celestron Edge HD

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#1 Acceptedplanet

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Posted 25 November 2021 - 03:35 PM

Hi

 

I have a Celestron Edge HD 8” and want to mount my Skywatcher Evoguide-50ED 50mm Guidescope.

 

I have been told I need to fit a CGE 8" bar and fit this to the top, then get a clamp to bolt the EvoGuide on so you can slide it up for balance. 
 

But still not sure how I would fit the EvoGuide to the clamp? What screws or bolts etc would I need and would all the holes line up etc. I know I can either have the small foot on it as in the picture or it can be screwed onto the small bar (came with bar attached)

 

Also would I need any different screws for the CGE bar?
 

Who has fitted this guide scope to theirs and what did they need? As there is no Astronomy shop near me so would have to order and prefer to get all that is needed. 



#2 mrlovt

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Posted 26 November 2021 - 12:04 AM

I don't have that combo, but since no one else has responded...

 

I believe you'll re-use the machine screws from the top of the OTA when you attach the accessory bar.  A lot of these are 1/4 20 thread sizes, but I don't recall offhand if that's what Celestron uses.

 

If you use a dovetail accessory bar, then a couple guidescope rings that clamp to the bar should work, replacing what came with your guidescope:  https://store-losman...tores.com/dvr66 That seems to me to be the simplest solution.  


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#3 DirtyRod

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Posted 26 November 2021 - 12:23 AM

ADM Accessories makes both a dovetail bar and rings in multiple styles that will come with hardware.


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#4 michael8554

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Posted 26 November 2021 - 04:33 AM

Is it too late to suggest that Off Axis Guiding would be better ?


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#5 rishigarrod

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Posted 26 November 2021 - 11:52 AM

I totally agree with the last poster. OAG is the way to go with long focal lengths.



#6 f430

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Posted 26 November 2021 - 11:57 AM

Here is a picture of the final set up on my 11" Edge HD. Parallax rings and ADM dovetail plate for the main scope, and ADM dovetail plate and rings for the guide scope. This was a very solid setup and worked fine. I used my ES 102 carbon fiber scope as a guide scope, but also as an imaging scope, with the 11" as guide scope. Whatever way you do it, it has to be very solid.

I also tried the large Celestron OAG, and it worked well, when it could find a star to guide on. If you image in an area with lots of stars you'll be fine. But try an area with few stars and you'll be pulling your hair out!

 

 

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#7 Seiten

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Posted 26 November 2021 - 04:44 PM

I refused for months to believe that I needed an OAG for my 9.25.  Then when I finally noticed that the stars were shifting frame to frame but my guide cam kept rock solid, i finally accepted the fact of differential flexure.  I new that all my mechanical interfaces I could touch were solid, from the mount all the way up to the guidecam.  What I hadnt considered was the hard-to-avoid SCT primary mirror flop.  Yes, the 9HD has mirror clutches, but they screw up the focus unpredictably.

 

Once I dove into  OAG world, worked out the back focus for both the in-axis and off-axis, images were rock solid!  All the grey-beards were right .... once again.  If you have a setup that doesnt have any differential flexure, consider yourself very lucky and go buy a lottery ticket.  May your luck be everlasting!


Edited by Seiten, 26 November 2021 - 04:45 PM.


#8 Acceptedplanet

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Posted 26 November 2021 - 05:02 PM

Looks a great setup, yea could just get a ADM Mini Dovetail & Guidescope Rings C8 Kit. Take the scope out the rings it comes with. 

Here is a picture of the final set up on my 11" Edge HD. Parallax rings and ADM dovetail plate for the main scope, and ADM dovetail plate and rings for the guide scope. This was a very solid setup and worked fine. I used my ES 102 carbon fiber scope as a guide scope, but also as an imaging scope, with the 11" as guide scope. Whatever way you do it, it has to be very solid.

I also tried the large Celestron OAG, and it worked well, when it could find a star to guide on. If you image in an area with lots of stars you'll be fine. But try an area with few stars and you'll be pulling your hair out!



#9 hmrphoto

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Posted 26 November 2021 - 08:27 PM

Is it too late to suggest that Off Axis Guiding would be better ?

Add another vote for Off Axis Guiding. The Celestron OAG has a big mirror. With a large guide camera- ASI 174 I have never had any problems with finding a guide star.



#10 Nicole Sharp

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Posted 26 November 2021 - 11:41 PM

Depending on your payload capacity, a side-by-side bar might work better.

 

An off-axis guider will not work for planetary autoguiding.


Edited by Nicole Sharp, 26 November 2021 - 11:42 PM.


#11 mrlovt

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Posted 27 November 2021 - 12:08 AM

ES 102 carbon fiber scope as a guide scope, but also as an imaging scope, with the 11" as guide scope. 

And I thought the ST-80 looked big on my 11".  Nice.  Yes, the ADM accessories are a very good value.




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