I'm not sure if I should post this in Observatories or in another forum, but I will try it here and see if it is allowed.
My observatory is going to house a 110 lb refractor mounted on a 10 Micron GM 3000. This mount is rated for
220 lbs. I have read that for astrophotography, you should have a mount that can carry "at least twice the weight
of your astrophotography setup". The GM 3000 carries "exactly" twice the weight of the refractor - without the added
weight of camera, filter wheel and OAG and Guide camera.
I'm wondering if any of you can tell me whether the additional weight of the camera setup and OAG will affect imaging
for me, since it puts the total weight at a little over the recommended ratio.
Any experience / response / wisdom you could share about this would be much appreciated.
Thank you in advance.
The simple, but illuminative view is this.
The "twice the weight" rule of thumb approximation is very rough. The weight spec of a mount is whatever the manufacturer wants to say it is. There are no rules, no standards.
In general, the more expensive mount manufacturers are more conservative in rating their mounts. The inexpensive manufacturers are in a very competitive mass market, they have incentives to push their weight ratings hard.
So, I would expect you'd be just fine.
One reason the rule is so rough is that weight is not the only thing involved here. Focal length magnifies mount errors, and success with a mount depends on focal length as it does on weight. Narrowband work generally involves exposures limited mostly by practical issues, such as having enough subs for good data rejection.
If it were me, I'd ask 10Micron. Their opinion beats the musings of people here who don't have a 3000. They have incentives to not paint too rosy a picture.