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#1 nganga

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Posted 02 December 2012 - 04:15 PM

Hello,

Anyone imaging with the EDGE HD 800 or AT8RC, OTA weight 14 - 15 lb, or thereabouts?
Is this a stable combination for this mount?
Any autoguiding issues?

Thanks,

Clem

#2 old_frankland

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Posted 02 December 2012 - 08:02 PM

I've been using a GM8 for lunar and planetary imaging with a C9.25. I would consider that maximum load with good stability. For deep sky imaging I have been using a 4" f/7 refractor. With guidescope, filterwheel and cameras, weight is about 22 pounds. Again, I consider that a comfortable weight max. When well balanced and polar aligned, the mount tracks well with PHD.

#3 Ranger Tim

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Posted 02 December 2012 - 10:59 PM

I think an eight inch RC or SCT is borderline for great stability with the GM-8. Better have everything perfectly balanced, etc. You are treading on the edge (pun intended - yuk, yuk).

#4 nganga

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Posted 03 December 2012 - 08:07 PM

Thanks for your responses.

Ranger Tim, I've been over that edge more times than I like; unpleasant experience :(

Clem

#5 Skyshooter

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Posted 03 December 2012 - 10:58 PM

I have a GM8 and use it with three different configs:
1)C8 with piggybacked ZS66, SSAG and 1000d DSLR, Rigel finder
2)SVR90T 90mm F/7 APO w/ ZS66, SSAG and 1000d dslr, Rigel
3)C8 with SVR90T, SSAG and 1000d dslr, Rigel finder

The only configuration I had any worries about was with the C8 with the SVR90T piggybacked. Even in that config. it guides well. I have to be more careful about the balance and do not use it that way often but it's do-able.

Cheers,
Ed

#6 nganga

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Posted 04 December 2012 - 07:54 PM

I have a GM8 and use it with three different configs:
1)C8 with piggybacked ZS66, SSAG and 1000d DSLR, Rigel finder
2)SVR90T 90mm F/7 APO w/ ZS66, SSAG and 1000d dslr, Rigel
3)C8 with SVR90T, SSAG and 1000d dslr, Rigel finder

The only configuration I had any worries about was with the C8 with the SVR90T piggybacked. Even in that config. it guides well. I have to be more careful about the balance and do not use it that way often but it's do-able.

Cheers,
Ed


Hello, Ed

Thanks for responding.

When you balance the mount in RA do you have a slight eastward bias as usually recommended? In DEC do you try to balance perfectly or slight camera or OTA imbalance?

Clem

#7 Skyshooter

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Posted 05 December 2012 - 12:43 AM

Hi Clem, Yes I do use a slight eastward bias. In Dec I balance the best I can. I swing the tube perpendicular to the ground on both sides of the mount and move the OTA forward or backward on the dovetail to achieve balance with the imaging goodies on the OTA of course. One other thing I have found is that when autoguiding you should turn off TVC. This really helped. I now have no subs I have to ditch except for the random satellite streak or aircraft that flies through my FOV.

Cheers,
Ed






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