Posted 23 October 2020 - 08:26 PM
I’ve been so confused by mount weight capacities.
If I look at the CGEM II, it has a weight capacity of 40lbs. But then Celestron sells a package with that mount and the 11” EdgeHD. The OTA is 28lbs, and then there’s 2x17lb weight. That’s a lot more than 40lbs.
So, for astrophotography, how much can I put on this mount? If 50% is the rule, if I have 22.5lbs if gear, is that too much for this mount? Because if I have to put counterweights on, I’d be at least 45lbs.
Posted 23 October 2020 - 08:33 PM
Posted 23 October 2020 - 08:44 PM
Thank you for helping.
Edited by dum-dum, 23 October 2020 - 08:50 PM.
Posted 23 October 2020 - 09:05 PM
I believe all the weight capacities for various mounts are the gear capacity. Weight amounts are not counted.
So 40 lb capacity is 40 lbs of telescope and related gear.
Posted 23 October 2020 - 09:19 PM
Counterweights do NOT count as part of the weight capacity.
Recommend you do *not* get the CGEM II for astrophotography. It's a great visual/planetary AP mount, but for DSO imaging they are not very consistent.
The "50% rule" means that below 50% of capacity tracking will not improve, but at 50% and up it will likely start to progressively deteriorate. That "likely" and the extent of deterioration, depends on several factors, but primarily the quality of your particular copy (mass-production mounts are not all alike, unfortunately, when it comes to the tolerances required for good tracking) *and* your skills in getting the mount ready (Polar alignment, level, balance, cord management) and guiding (parameters, seeing evaluation, etc, etc.).
The 50% number was selected for convenience. Nobody has examined to see if it should be 47% or 58% .
Assuming you get a "good" CGEM II, and that you are knowledgeable about how to guide it, 22 or 28 lbs should not present any problem.