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CEM70 with 12 inch newtonian

iOptron CEM70 iOptron CEM70-NUC Equatorial Mount Reflectors
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Ori Shabtay avatar
Ori Shabtay avatar
Hi, i wanted to ask if i should go with Ioptron CEM70 mount with non crabon tube 12 inch newtonian.

the weight capacity of the CEM70 is 32kg and the scope is 25kg without all the rest of the equipment.


wanted to know if someone has such setup and if it's too risky etc. 

if so, is there other trusty mount that can go up to 35-40kg that you recommend?


thank you
Stjepan Prugovečki avatar
Stjepan Prugovečki avatar
I have CEM70, it is an excellent mount. Did not try something that heavy , but it would be at the upper edge , if not beyond. It might work, but I think that the setup for AP should not exceed 70% of max. spcified payload . Therefore CEM120 would be a far better choice .
Riccardo Civati avatar
Riccardo Civati avatar
for me that telescope is too heavy, remember that for photographic use you have to stay under the specified weight.
I have the cem70 and the entire optical part weighs about 16 kg
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Nick Grundy avatar
Nick Grundy avatar
I love my CEM70 (it performs nearly as well as my new series 6 MyT) though I stay around 40-50lbs on the CEM70. 

I would go for the CEM120, or check around to see if you can pickup a used mount with good capacity (just saw a nice looking Paramount MX for 5k)

Especially for iOptron, I feel like the nice place to be is about 50-65% of the max payload. (just given my own experiences with CEM70, HEM's, GEM's)
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Ori Shabtay avatar
Ori Shabtay avatar
thank you all for the replies and help
Tim Hawkes avatar
Tim Hawkes avatar
I use an Orion (OK) OO VX12 on a CEM70 and the CEM70 copes OK with it.  See some examples in my gallery.  The VX12 is one of the lighter 12 inch scopes but with top plate, rings guide scope and a long dovetail the total weight  is well over 20 kg.  Nevertheless I have had good guiding-  although much of what I have done with the VX has been short sub lucky imaging - subs as long as 3 min have been fine (when not too windy).  The thing is to be very careful about getting the balance spot on and the order you do things when loading all that weight on – there is the potential for damage if the clutches aren't off when they need to be etc.
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SeulWoo Kim avatar
SeulWoo Kim avatar
That’s exactly the setup I’m using.
The guiding accuracy varies depending on the seeing conditions, but during the good summer seeing, it averages around 0.5 to 0.6 arc seconds.
If you’re using a lower pier height below the mount, mounting telescope shouldn’t be too difficult.I have many photos taken with that system.
https://www.astrobin.com/ri1cev/E/
https://www.astrobin.com/0tl9t5/
https://www.astrobin.com/a0ejbi/

andrea tasselli avatar
andrea tasselli avatar
If it is anything like more than a whiff of wind you're done with your guiding accuracy. And I have a much larger mount.
Jay Hovnanian avatar
Jay Hovnanian avatar
@Ori Shabtay  ~  I don't disagree with much that has been said above ... and @andrea tasselli  is certainly correct about exposure to wind ....

Will your set-up be permanent and / or shielded from the elements?  Another relevant consideration is the weight of the CEM120 head.  It is a veritable beast.  Setting up and breaking down the CEM120 would likely be a challenge for many of us.

I have occasionally mounted my Meade SN10 on my CEM70 for AP.  Though not a 12" Newtonian, it does have two pieces of glass, and I utilize a fairly heavy custom counterweight system to 3D balance this OTA on the DEC axis.  So, I am thinking that set-up probably approaches the overall weight of a 12" Newtonian.  The wind notwithstanding, my CEM70 handles the Meade without any issues whatsoever.

I have never been concerned with percentages, and seeing is a factor in every environment ... so perhaps your 12" Newtonian would be okay on a CEM70 ....
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Ori Shabtay avatar
Ori Shabtay avatar
Jay Hovnanian:
@Ori Shabtay  ~  I don't disagree with much that has been said above ... and @andrea tasselli  is certainly correct about exposure to wind ....

Will your set-up be permanent and / or shielded from the elements?  Another relevant consideration is the weight of the CEM120 head.  It is a veritable beast.  Setting up and breaking down the CEM120 would likely be a challenge for many of us.

I have occasionally mounted my Meade SN10 on my CEM70 for AP.  Though not a 12" Newtonian, it does have two pieces of glass, and I utilize a fairly heavy custom counterweight system to 3D balance this OTA on the DEC axis.  So, I am thinking that set-up probably approaches the overall weight of a 12" Newtonian.  The wind notwithstanding, my CEM70 handles the Meade without any issues whatsoever.

I have never been concerned with percentages, and seeing is a factor in every environment ... so perhaps your 12" Newtonian would be okay on a CEM70 ....

i see, i guess it's better to go with 10 inch instead with that mount to be sure. it will be exposed to wind sometimes and won't be shielded much.

thank you very much for your guidance and help in the matter