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Direct drive mounts are used in recent professional telescopes mounts and is the state of the art. Here are in a nutshell the main advantages:
- No gear, and no worm and no belts: no maintenance, no mechanical wear, no summer-winter gear and worm tuning
- Semi absolute encoders: no periodic error, accurate positionning and speed accuracy, very smooth motion
- High speed and noiseless slewings
- Long unguided exposures (15 min with 2m focal length): no guiding camera is necessary!
Further advantages of the Alcor-Sytem Nova:
- Axis brake: This mount has current loss magnetic brakes to ensure telescope tube safety
- Because axis have large hollow, any cables for camera and any instruments can be passed thru the axis.
- On startup the mount knows where it is located on the sky due to absolute positionning system.
The Nova mount works so close to perfection, that if the Optical Tube Assembly (OTA) is stiff, it can acheive long unguided exposures. If the tracking/speed model (from the pointing model) is enabled within the software mount, the mount can compensate for bad polar alignment.
- Motors: One high torque frame less brusless motor per axis
- Encoders: 67 millions steps per rotation (26 bits), Absolute encoders 0.019 arsec per encoder step
- Moving speed: 20°/s
- Pointing accuracy (with Pointing model): down to 5 arcsec rms
- Tracking accuracy: Better than 0.25 arcsec in 5 min
Tracking fast objects: The mount (and the software) can move the mount at asteroid motion rate (plus the sidereal rate, refraction rate and tracking model rate). The image shows a 600s exposure with speed object enabled. The asteroid is pin point sharp and this is not anymore required to split the exposures so that the asteroid does not trail! The mount is able to perform earth artificial satellite tracking, based on satellite TLE that is used to predict their trajectory. This can be possible with low orbit satellites such as ISS. The mount prepares it position on the satellite path, and start tracking when the satellite appears over the horizon. The mount software can retrieve from the internet TLEs and perform computations of the satellite pass.
The software is a very advanced software, that includes Tpoint pointing model, as well as speeds model to compensate for non perfect polar alignement. It has an ASCOM interface, so that any ASCOM compliant software can drive the mount.
The mount comes without counterweights! Optional available are Counterweights, a pier and polar finder.