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Guide Scope Recommendations for C8

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#1 satellitespotter

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Posted 24 June 2019 - 04:23 AM

Hi everyone,

I am somewhat new to astrophotography and after about 6 months I have decided to invest in a guide scope setup. Does anybody have any recommendations for a good scope and camera. I'll be using my Celestron c8. 

Thanks, Nick



#2 Tapio

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Posted 24 June 2019 - 06:46 AM

Are you planning to image using C8 @ 2000mm with AVX mount ?

Personally I wouldn't recommend it.

With f/6.3 reducer little better.

OAG is common recommendation with classic C8 scope.

 

I admit I used basic 50mm (about 160mm fl) guide scope with f/6.3 reduced C8. Mount was HEQ5 Pro/Sirius.

And I still use such guide scope with C8 and CEM60-EC.



#3 StarmanDan

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Posted 24 June 2019 - 11:03 AM

I use an ED80 and ZWO ASI120mm with decent results, but I am using a .63 reducer with my setup.  The native f10 will be very difficult.  An OAG is typically recommended for SCTs to combat mirror shift.  If your SCT has a mirror lock, you may be able to get away with a guide scope, but you will likely be over the weight limit for the AVX.  My 8" SCT set up with everything on it is just over 30lbs and my mount is feeling it.  I use an Orion Atlas.  



#4 ELDavis

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Posted 24 June 2019 - 12:52 PM

I have a 8" Celestron and always use a F6.3 focal reducer. I have been quite happy using the Orion SSAG. In the old days of film imaging I used an OAG. However, I have found the SSAG so much easier to use - no focusing issues, and guide stars always in the field of view. I wouldn't dream of going back to the OAG.



#5 t-ara-fan

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Posted 24 June 2019 - 02:30 PM

A familiar tale:

 

  • On my HEQ5 pro mount, EdgeHD-8, 0.7x reducer, I used an Orion MMAG kit (163mm FL) guider. It worked OK with a 0.7x reducer on my EdgeHD-8 mounted on a HEQ5 pro mount.  Worked VERY well with my 80mm refractor.
  • But I wanted better.
  • So I added a ShortTube80 on top of the EdgeHD8eDG, with a 3 ring set, and a big Losmandy dovetail bar.   Darn too heavy (5-6 pounds for all that). It did work at 2032mm FL, but not very well.  Lots of bad subs.
  • So I added a Mach1GTO and deleted the HEQ5.
  • Works great at 2032mm or 1422mm FL!!
  • I have started dabbling in 600" subs.
  • So I bought a ZWO OAG and ZWO ASI174MM mini. I picked those up 2 days ago, haven't tried them yet.

 

TL;DR:

To have great success you need a focal reducer and maybe a better mount. That scope would be great for planetary and lunar work, just need a small "video" camera, no guiding or mount upgrade required.   For DSOs, shorter exposures will compensate for a lesser mount, but at f/10 you won't get many photons.

 

Starting DSO photography with a C8 is challenging, sort of like jumping in the pool at the deep end to see if you can swim.  An 80mm refractor would be WAY easier to use and get good results.



#6 satellitespotter

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Posted 24 June 2019 - 03:59 PM

Hi everyone, thanks for your responses,

I will be using a f/6.3 reducer.

Thanks, Nick




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