The Losmandy G-11 has been the entry level mount of choice for imagers on a budget for a number of years. The GM-8 is not stiff enough to be a good imaging mount.
Ron Wodaski: The New CCD Astronomy, p133.
He goes on to say that unguided exposures with the G-11 are often problematic due to tracking errors, and recommends using an autoguider.
Another quote: The G-11 is a good choice if you are on a tight budget, but expect to put in some time tuning the mount and learning about its behaviour under load.
Personally, I have taken many images with my GM-8, often in quite windy conditions, and whatever faults these images may have, tracking has never been a problem, both with manual guiding and autoguiding, although I have never tried unguided track and stack.
Geoff
In general, I'm a bit disappointed with my Losmandy GM-8. Backlash I simply can't get rid of, needing to tweak gears, that kind of thing really disappoints and annoys me. But I still manage to get photo's using with little problem/work-around.
The comment "is not stiff enough" is really odd, I'd say the thing is rock solid for it's weight capacity. Doesn't budget in a strong wind. Wouldn't know if there's flexure issues, but I haven't noticed problems caused by flexure.
Another quote: The G-11 is a good choice if you are on a tight budget, but expect to put in some time tuning the mount and learning about its behaviour under load.
I have to say that my 'budget' is a wee bit tighter than that
The G-11 has undergone many evolutionary changes, which are not externally obvious to the end user, and have been made since Mr Wodaski wrote his comments some years ago.
Current series mounts have bronze worms, thicker gears, better bearings and
there is a double worm bearing assembly in beta testing now.
In short, they are more rigid and track better now than ever before. Many users are reporting +/- 4 arc sec raw PE with a very smooth transition over the 4 minute period.
It's been said before that a G-11 is either an entry level mount for a serious astonomer, or a high end mount for the average amateur. Since I don't see myself splashing out 8 or 9 grand for an AP Mach1GTO, I'd class myself as the latter
