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ourobouros2k2
sage


Reged: 11/10/11

Loc: okc area, oklahoma
Re: guidescope guiding a 8SE SCT new [Re: foste1cc]
      #5670690 - 02/09/13 12:54 PM

I didn't use the dovetail that came with the package. I used a celestron losmandy D rail and astrotech adapters to mount the scope. In addition to cleaner appearance, it is much more rigid which helps eliminate flexure. Here is my setup:





without the scope and rings:



attachment points:



Remember this adds more weight, so only go this route if the mount can support it. For AP, I am at the limit of payload for the Sirius EQ-G, and even then I have to get a counterweight bar extension to balance the load properly.

The celestron los-D rail for 8":

http://www.astronomics.com/celestron-dovetail-plate-8-inch-optical-tube-losma...

Astrotech adapters for mounting rings:

http://www.astronomics.com/astro-tech-dovetail-accessory-adapter-losmandy-d-p...


Another option you could try that lets you use the stock bar with the SSAG package is ADM radius blocks. These are spacers that enable you to get a more secure fit for the bar. No matter what you decide to do, you will be looking at some extra cost associated with adapters to mount a dovetail bar. Hope it helps,

Andy


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Midnight Dan
Postmaster
*****

Reged: 01/23/08

Loc: Hilton, NY, Yellow Zone (Bortl...
Re: guidescope guiding a 8SE SCT new [Re: ourobouros2k2]
      #5670728 - 02/09/13 01:12 PM

Quote:

do any of you know if celestrons 125mm rings they sell for their guidescope, will fir the ST80?




I just measured my ST80 and the outside diameter is 90mm. I don't know what the range of sizes is for scopes that fit the celestron rings. But, Orion has a variety of rings and they recommend their 102mm rings for scopes of up to 80mm aperture.

ADM sells very solid and well made guide scope mounting kits which you can buy with the parts needed to mount to your particular OTA:

Mini-dovetail bar: http://www.admaccessories.com/MDS_guidescope_kit.htm
Vixen dovetail bar: http://www.admaccessories.com/V_Series_Guidescope_Kit.htm

-Dan


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foste1cc
super member


Reged: 01/06/13

Loc: Armada, MI
Re: guidescope guiding a 8SE SCT new [Re: Midnight Dan]
      #5670785 - 02/09/13 01:38 PM

Thanks for the pics and info Andrew! And Dan, thanks for measuring and for the links! I was thinking about getting celestrons mounting rings and dovetail bar, and getting orions ST80, but am now reconsidering celestrons guidescope. I see it's a little heavier than the ST80 and has 600mm focal length compared to the 400mm on the ST80. I know your guy's discussion about the focal length in this thread, but having my 8SE, if it were you, would you guys go with the ST80 or celestrons 80mm guidescope?
This will mainly be a guidescope, but i'd like to tinker around with AP through the guidscope if possible. I'm assuming the ST80 would be better in that case since it's at f/5 compared to celestrons 7.5?
But my main imaging will be coming from my 8SE OTA until i can upgrade. So as mostly just a guiding scope for my OTA, which would you guys take??

Edited by foste1cc (02/09/13 01:58 PM)


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Midnight Dan
Postmaster
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Reged: 01/23/08

Loc: Hilton, NY, Yellow Zone (Bortl...
Re: guidescope guiding a 8SE SCT new [Re: foste1cc]
      #5670882 - 02/09/13 02:56 PM

Hi Carl:

Probably not big difference one way or the other. I don't think either one will be particularly great for AP because they're both achromats and will show a fair amount of false color. But you can certainly use either to play around with it. But I think I'd give a slight edge to the ST80 just because of the lighter weight.

Keep in mind that with mounts in this rage (30 pound capacity), the weight rating is for visual use. For AP, it is recommended to load the mount at 1/2 the rated capacity for best results, 2/3 at most. That means that the mount should be loaded with 15 to 20 pounds of gear. When you start adding up the weight of the main OTA, camera, guide scope, autoguider, mounting hardware, adapters, finders, etc. ... well it adds up quick!

Some would say that an 8"SE with a full compliment of gear is pushing the limit for this kind of mount, especially given its long focal length. On the other hand, going back to that "how particular you are" statement, there are many who do use this kind of setup on a CG-5, Sirius, or HEQ5 mount and get good results.

But in any case, weight is a concern and the lighter you keep your rig the better. That would make me lean towards the ST80.

-Dan


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foste1cc
super member


Reged: 01/06/13

Loc: Armada, MI
Re: guidescope guiding a 8SE SCT new [Re: Midnight Dan]
      #5670892 - 02/09/13 03:06 PM

Thanks Dan! That helps out!

Edited by foste1cc (02/09/13 03:07 PM)


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