Author Topic: For the last time: GM-8 15lbs vs 30lbs  (Read 233 times)

Tyler Fonseca

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For the last time: GM-8 15lbs vs 30lbs
« on: December 28, 2017, 11:32:41 AM »
Can anyone SHOW ME the difference in tracking quality between a Losmany GM-8 loaded to 15 pounds and the same one loaded to 30 pounds? I guess some tracking plot? I don't know how to do that stuff yet, and I don't think I can even come up with the 30 pounds of equipment. Plus, I just have the stock worms and blocks.

I'm going through a Cat Crisis. I can't seem to buy an old Celestron 8 with out feeling sorry for it and getting it an old fork/wedge/tripod to put it on, instead of just slapping a bar on it and putting it on my GM-8! I'm even going to end up with an extra fork after this weekend.

My *only* recourse is to just buy a new Edge scope that was never attached to a fork. What I'm trying to figure out is if my GM-8 can handle the 9.25" scope (20 pounds) with all the extra parts for photography which will for sure bring it up into the 30 pound area. If it really can't handle it then I'll go with the 8" (13 pounds). I'm not going for National Geographic quality pictures or anything, but if 30 pounds is REALLY going to be a lot worse then I'll stick to the 8" like the mount was made for.

Are there plots on the web somewhere?

I really need to see a shrink.

Thanks!

Bob



Lance Soto

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Re: For the last time: GM-8 15lbs vs 30lbs
« Reply #1 on: January 12, 2018, 03:08:07 AM »
It's not just the 30 lbs, it's the long focal length of the scope. I don't have a GM8 or any graphs to show you, but I'd be willing to bet you'd be very under-mounted with the GM8. You would be very sensitive to even the slightest wind, and you'd have to get everything totally right to even have a chance.

Much safer to go with the Edge8 and get a reducer. There's going to be little advantage to a 9.25" vs. an 8" for AP. Even for visual (there I've had both scopes) the 9.25" is only (marginally) superior to the 8" when you're at a dark site, or if you have great optics and are in a great seeing location. And if it's a question between a regular 9.25" and an Edge8, I'd take the Edge 8 any time for AP *or* visual. Mine is super-sharp.

Devon Dank

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Re: For the last time: GM-8 15lbs vs 30lbs
« Reply #2 on: January 12, 2018, 05:40:39 PM »
That's what I'm wondering. Everyone says more weight is worse (and, yup, you're right, more mm's too), but I'd just like to know how much -- however it can be quantified. I can't imagine I won't get a bigger mount someday, but no time soon where the 9.25 will be fine. Will the 9.25" just be a royal mess to deal with until then...or maybe will it not really be that bad. I'm looking for some kind of numbers.

Otherwise, yeah, I agree with you. There was a big thread a while back about 8 Edge vs 9 regular. I think I would go Edge either way. And with the 8 the extra $1000 won't be under appreciated, either.

Thanks!

ermaudyvi

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Re: For the last time: GM-8 15lbs vs 30lbs
« Reply #3 on: January 13, 2018, 02:51:17 AM »
Thinking more about this...

If I have a C8 on the mount and it comes out to 15 pounds, then I throw a 15 pound bag of sand on top and rebalance the mount does it become twice as unstable? Four times? Only half again? Or does a weight change like that even matter much? I don't know what the units of instability are.