The OGEM (Open German Equatorial Mount) is a servo powered (kinematic) friction drive mount. This system is renowned for high precision and reliability. The mount comes with several patented features and a flexible open source modern control.
The mount is designed to carry 100 kg (this is enough for a 500 mm catadioptric or a 200 mm refractor). The advised maximum payload is 75 kg, this should be reduced with particularly demanding systems, such as refractors due to their length.
The mount is constructed for outdoor use, all surfaces have some form of heavy duty protection. Aluminium is hard-coat anodised, steel is galvanised and powder coated, the system is built to survive many years outdoors and if the environment is particularly tough there is an option to upgrade to stainless steel drive wheels. The drive wheels are already high grade steel and very rust resistant but your requirements may vary. 30 kg of counterweights will be provided with the mount.
To lower the barrier to entry as much as possible, the base model OGEM will be supplied without encoders or any material upgrades. The mount uses servo motors instead of steppers and the controller is the same on all models meaning upgrading to encoders at a later date is something the client can do themselves with a minimum of mechanical skills. The encoder system provides 0.08 arcsecond resolution, enough for even the best sites on the planet. With guiding or encoders you can expect 0.1 to 0.2 arcsecond peak to peak tracking error. This may increase when you approach the limits of the mount but will remain undetectable at the eyepiece/CCD camera. An added benefit to the encoders is that the mount will never lose it’s position when knocked or due to a power cut.
The mount can be controlled via joystick, computer, laptop, smart phone or tablet. There is a Windows driver, an Apple driver in the pipeline and hopefully the Linux community will take advantage of the open source control system. The mount connects via Bluetooth or USB. The system is ASCOM compliant and will come bundled with Stellarium but you may use any software that supports ASCOM.
|Payload (kg)||100 (advised 75)|
|Axle diameter||50 mm RA, 40 mm DEC|
|Axis encoder resolution (Arcsec)||0.08|
|Control system||FreeGo2, ASCOM compliant & Open Source|
|Slewing speed (deg/s)||5|
|Pointing accuracy (arcsec)||<30|
|Typical PE (Arcsec RMS)||<0.2|
|Weight (kg)||30 (14 kg base and 16 kg body)|
|Power (v DC)||12|
|Maximum current (A)||0.8|
|Current pull during tracking (A)||0.15|