10Micron is an Italian company that is 100% focused on making high-end telescope mounts. From small mounts used by amateurs to large mounts used in professional observatories. The GM2000HPS II Combi is the second smallest in the collection. The total weight is about 33kg, so pretty impractical for any mobile use. However, the mount can be taken apart into two pieces of 18 and 15kg respectively, which makes it remarkably easy to carry around. Maximum load capacity is 50kg. The GM2000HPS is equipped with absolute encoders. These are high-precision devices that allow the mount to know it’s exact position with <20 arcsec precision. And it remembers this position at all times, even if you unlock the clutches and rotate the mount manually. The absolute decoders allow unguided imaging with exposures up to 15-30 minutes.

For unguided imaging, a mount-model is required. This model is built by taking images at several positions and plate-solving those images so that the actual RA and DEC can be determined. A model needs at least 3 points, but the more points, the better. With enough points, the mount can correct for tracking errors and flexure, atmospheric refraction, etc. Building a mount model can be automated using software such as MountWizzard4, which is specifically designed for 10Micron mounts. This mount is permanently stationed at the observatory in Spain, where the models typically have 80-99 points. One of the benefits of using mount models is that small deviations in polar alignment or levelling are automatically corrected. If polar alignment is not completely perfect, there is a small risk of field rotation, but only when imaging at high altitudes (>80°) and long exposures (>15min).

The GM2000 HPS II COMBI is controlled with exactly the same control-box and hand-controller as the GM1000HPS. For details, see below. For firmware updates and updates on comets, satellites, as well as earth rotation data, a small piece of (Windows only) software is provided by 10Micron. In this blog post there is more detailed info on how this works.

The GM1000HPS is the smaller brother of the GM2000HPS mount. Its weight is about 20kg and maximum load capacity is 25kg. Also the GM1000HPS is equipped with absolute encoders. By no means is this a portable mount, but at a weight of 20kg this mount can be transported rather well. Add to that the ability of unguided imaging, and effectively this mount is up and running almost as fast as a true mobile mount, like the RainbowAstro RST-135E mentioned below.

Important is to level the mount well and point as close to the north as possible with a regular compass. Using MountWizzard4 a quick 3-point model can be built in about a minute. The software will give quantitative information on how many fractions of a turn both the azimuth or altitude adjustment knobs need to be turned. Then running a second automated 3-point model will likely give a fairly good result. Any polar alignment error < 5 arcmin is considered acceptable. Once within that limit, running a final 18 point model will give enough precision for a mobile setup with focal lengths up to 1000mm to run unguided.

The mount runs on 24V DC power and is controlled via a separate control-box that houses a Linux-based computer. The control-box can be controlled using either the hand controller or a PC. Connection with the PC can be established using either WiFi, Ethernet or RS-232/USB.

Rainbow Astro is a Korean company that has its origins in robotic engineering. They produce a line of telescope-mounts using strain wave gear or harmonic drive motors. These motors are known to combine a lot of torque in a small package, are very precise in their movement and have almost no backlash, ideal properties for an astronomical mount. In the case of the RST-135E, the mount weighs only 3.4 kg, but can hold a 13.5kg rig unbalanced or 18kg balanced. The Rainbow Astro was one of the first to bring out such mounts, but today there are several competing products on the market, including the NYX-101 from Pegasus Astro and the AM-5 from ZWO.

The RST-135E is a relatively new version of the mount, and includes an encoder on the RA axis for better tracking performance. In contrast to the GM1000HPS, this mount can not be used unguided. The precision is not good enough for that, and also an encoder on the DEC axis is missing. Pointing accuracy is very good. After a polar alignment, syncing just one blind plate-solve is often enough to put any selected target right in the middle of the field of view. There is a native INDI driver for the mount, so it can be fully controlled through KStars/Ekos.

The claim to fame of this mount is its portability. One can carry it in a backpack and set it up in minutes. Portability and versatility are the two main reasons why this mount was added to the observatory. It allows the setup of a second rig without too much hassle, and can be used with the FSQ-106 or the Mewlon-180c. Alternatively it can be taken as the main rig with one of these scopes to a remote dark-site, to capture a faint nebula or a planet that is low on the horizon. Also lucky imaging applications, such as solar, lunar and planetary imaging, work well this mount. The mount can even be used as a tracker for photography with regular mirrorless cameras and their lenses. The Perseid meteor shower for example was photographed using this mount. It combines a lot of use-cases which make it a very versatile addition to the observatory.