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#1 CarolG

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Posted 11 May 2013 - 09:43 AM

Soon I will be ordering an Astro-Physics 1600 GTO mount. The only experience I've had with equatorial mounts is my ASGT5. The counterweights that came with it have worked just fine. But I'm not sure how much counterweight I'll need and the best combination of weights to create the most flexibility. Right now I figure the scope (C14HD)and accessories will weigh in at between 75-90 pounds, depending on my various setups. I've read that the amount of counterweight should be about 80% of one's payload. How do you all figure it, and what do you think would be the best combination of weights? AP's options are 5, 10, 18 and 24 pound weights. I really appreciate any help and advice you can give.

#2 MartinTreadgold

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Posted 11 May 2013 - 10:07 AM

I have a similar issue with my VX mount with my Nexstar 5SE tube, the tube is too light, that i have to move the counterweight all the way up and it sometimes hits the mount body... so I need a lighter counterweight... or buy a bigger tube...

#3 CharlesW

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Posted 11 May 2013 - 10:26 PM

I have my C14 on a Paramount MX and 60 lbs is barely balancing it. If you are going to be imaging, I'd shoot for a minimum of 80 lbs.

#4 EddWen

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Posted 12 May 2013 - 11:33 AM

Carol,

A-P has an option for a longer c-weight bar that provides more flexibility.

Call George Whitney at A-P. He loves to talk to people about their mounts.

#5 foggylenses

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Posted 12 May 2013 - 04:23 PM

what size is the bar?

#6 Tom and Beth

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Posted 12 May 2013 - 06:19 PM

This is very helpful to calculate how much weight.

#7 CarolG

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Posted 12 May 2013 - 09:32 PM

Thanks so much for all the help. This is probably a dumb question, but how does the longer bar give more flexibility? Can you have fewer pounds if they are distributed over a greater distance? I will definitely give George a call. Thanks, Edd. Tom and Beth, thanks for the link. I will have to study it. Also, Casady may be another option for finding counterweights. I read that the things Casady makes are machined at the Casady 'n Company shop in Oklahoma City just a few miles from my home.

#8 rdandrea

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Posted 13 May 2013 - 08:37 AM

Can you have fewer pounds if they are distributed over a greater distance?


Yes, but there's a tradeoff there. A longer bar means a longer moment arm which means lower frequency vibrations. As long as I'm within the capacity of the mount, I'd rather have more weight on a shorter bar.

#9 EddWen

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Posted 13 May 2013 - 12:44 PM

I have a self-made extention on my A-P1200 to offset a 114 lb. Payload. There are no low frequency vibrations.

Clear skies,


Can you have fewer pounds if they are distributed over a greater distance?


Yes, but there's a tradeoff there. A longer bar means a longer moment arm which means lower frequency vibrations. As long as I'm within the capacity of the mount, I'd rather have more weight on a shorter bar.



#10 Tom and Beth

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Posted 13 May 2013 - 12:58 PM

Thanks so much for all the help. This is probably a dumb question, but how does the longer bar give more flexibility? Can you have fewer pounds if they are distributed over a greater distance? I will definitely give George a call. Thanks, Edd. Tom and Beth, thanks for the link. I will have to study it. Also, Casady may be another option for finding counterweights. I read that the things Casady makes are machined at the Casady 'n Company shop in Oklahoma City just a few miles from my home.


That would save you on shipping. There's a rumor going around that he's closing shop. Don't know if it's true or not.

I have weights from AP and Robin. No noticeable difference in fit. Neither seems to mar the CW bar. Both hurt if they land on your toe or fingers.

#11 orlyandico

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Posted 13 May 2013 - 02:03 PM

I heard that Casady is going out of business...






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