3 replies to this topic

[Reachforthestars360]

Alright so I recently aquired an observatory, I have no prior background with anything about telescope or their electronics. I've posted a few times on Facebook and I'm sure some of you may recognize the scope from there. I'm trying to upgrade the drive system for RA and DEC. Currently they are old ac motors 100oz inch at 1 rpm, and use a hand control. The motors are dead and don't work, id like to use something like the onstep v4 pro but unsure if the nema 17s can move this or if id need to build it from scratch.its a big fork mount with a 12 ft housing, 16 inch mirror and 2600mm FL.

[Overtime]

How heavy is it?

[TOMDEY]

Some pictures would help. A properly designed, built, and balanced scope should require very very little torque to drive it. I had a nice 650-lb German Equatorial that reliably drove and auto-tracked + corrected both axes powered by tiny motors. But the scope was meticulously balanced, good bearings, great drives. RA was Byers 11+ inch with traditional synchronous drive motor and freq-controller input to do the drive correcting for atmospheric etc. The Dec Drive correction was my own design and build, powered by a tiny reversible 12VDC. I'd do multi-hour single exposure imagery at 2000mm focal length with no issues.    Tom

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[duck]

overcoming friction is part of it.  Out-of-balance load is another part.  But if you want to slew at 4 deg/sec, moment-of-inertia and max motor speed become issues.

 

In the olden days, some telescopes that slewed had two motors on each axis, engaged/dis-engaged by electric brakes.

 

I tried a home made planetary differential, ala Texerau, but failed spectacularly.  Even then you need brakes.