The mount I use for astroimaging is Losmandy GM 8 german equatorial mount. Mount has 30lbs instrument capacity, but when it is used for imaging 20lbs is more realistic value. It handles my ZS105ED telescope and ST2000XM CCD camera with CFW10 filter wheel without any problems. My mount is variant equipped with stepper motors and digital drive (no GOTO). At the time I ordered the mount (May 2006), GM8 was shipping with high precision stainless steel worms.

There were several reasons I chose this particular mount. Since I don't have a permanent setup I often have to carry the mount in and out using stairs. It is important to me that the mount is not too heavy and that is easily disassembled into manageable parts. Losmandy GM8 is a mount that I can easily maintain and even repair myself if the need arises. All of the spare parts can be ordered and shipped separately. For most of the other mounts, if they get broken, the only option is to ship them back to factory. That's not so simple to do from Croatia, and it takes time and money. And finally, Losmandy GM 8 is a precise enough mount for astroimaging and it can be autoguided by CCD camera.


Losmandy GM 8 is almost completely made of precisely machined aluminum. Counterweight shaft is made of solid stainless steel. Finish of the mount is very good and the mount looks nice and solid. Built in bubble levels in combination with adjustable tripod make it easy to level the mount. Azimuth and altitude adjustment knobs are big and precise enough to easily achive good polar alignment. Polar scope is an option for the mount, useful for the initial alignment and visual work. For astroimaging drift alignment is neccessary.

For unattended astroimaging very nice feature of GM 8 are clutches on both shafts. So, if the scope hits the mount during the imaging session the clutches just slip, and no damage is done!

In order to properly balance my setups I ordered couple of counterweights from Robin Casady. They are made of solid stainless steel and look much nicer then the standard ones provided by Losmandy. I also replaced plastic motor covers with machined aluminum ones (available for stepper motors), which provide better protection from accidental bumps. There are also many other improved parts available for GM 8, like knobs, levers and adapter plates to replace the standard ones. Most of them are not essential, but make life easier or improve looks of the mount.


Many people say that the adjustable tripod is the weakest point of GM 8. Some claim that with better tripod or pier they managed to significantly increase the mount's capacity. In any case, the tripod does adequate job for me. Good thing is that it is not heavy and it's collapsible, so one can easily carry it arround. My only complaint is that the legs of the tripod are not finished with some rubber feet. Aluminum profile of the leg is just cut at the end. That is why I put Celestron Vibration Supression Pads beneath the legs. They do good job of preventing vibration transmission from concrete floor to the mount.

Update September 2008:

I've replaced the original RA worm and worm block with high precision brass worm and single piece stainless steel worm block produced by Ovision. It is an improvement of the original design. I've never had much time or will to measure periodic error of the mount before and after the upgrade. But my subjective feeling is that the upgraded mount tracks better. Before the upgrade I've lost a subframe now and then due to the guiding problems. After the upgrade I've never lost a single frame, and tracking errors are smaller than before under the same circumstances. To conclude: I'm happy with the Ovision upgrade.


Update August 2016:

I have extended the GM 8 RA axis with spacer I've got from Teleskop Service. Original 15mm distance to declination block is increased to 50mm. That makes it less likely for the telescope/camera combination to collide with the tripod or the mount itself during the imaging session. Also gives you a limited capability for tracking after the meridian. Now I have less problems imaging objects near the zenith and I can track objects longer during the night. Stability and looks of the mount are not impaired. Had some problems during the installation of the spacer, since the original screws were a bit too long. The spacer was a bit loose, but the problem was solved with a couple of washers. To conclude: a useful upgrade for GM 8 if you are doing astroimaging.