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question about eq platform for dob

Started by rfiol , Dec 06 2021 11:40 AM

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6 replies to this topic

#1 rfiol

Vostok 1

topic starter

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Joined: 02 Sep 2020
Loc: Miami, FL USA

Posted 06 December 2021 - 11:40 AM

I'm designing an equatorial platform for my dob, and have decided to go with the VNS (Vertical North Segments) design. My question is: Why not a VSS also? I've yet to see a design with a vertical south segment. Possible? Practical?

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#2 thoughtwave

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Loc: Berkeley, CA

Posted 06 December 2021 - 07:58 PM

It should be exactly the same principle, just reverse the direction of the motor.

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#3 Ed Jones

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Posted 06 December 2021 - 08:52 PM

I think he means both bearings would be vertical. I think it would "float" and need constraining.

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#4 Tom Stock

Apollo

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Joined: 27 Jun 2010
Loc: Saint Augustine, FL

Posted 06 December 2021 - 09:30 PM

I'm designing an equatorial platform for my dob, and have decided to go with the VNS (Vertical North Segments) design. My question is: Why not a VSS also? I've yet to see a design with a vertical south segment. Possible? Practical?

I believe it would just make the platform larger than it needs to be.

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#5 rfiol

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Loc: Miami, FL USA

Posted 07 December 2021 - 09:01 AM

I think it would "float" and need constraining.

Thanks, Ed. This is what I was thinking, and it seems to be the only (albeit significant) downside.

Edited by rfiol, 07 December 2021 - 09:02 AM.

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#6 Rodastro

Sputnik

Posts: 34
Joined: 07 Sep 2014

Posted 08 December 2021 - 05:18 PM

The club I belong to (Astronomical Society of Victoria) has an Instrument Making section and we’ve built I think about 15 platforms with two vertical sectors. Mark Justice runs the section and developed the design below. The top board is constrained by two bearings. The green rollers are conical and made to rough shape on a 3D printer. They are then spun with a drill while in position against a razor blade to smooth the surface.

The platform below is the only one we have made that has a second motor for limited dec adjustment. The second motor has a cam attached to it. This platform also has a hand pad. I’ve used it a few times and it works nicely. The hand pad is very helpful for high power viewing of planets.

As you can see the stepper motor drives both sectors which adds stability.

We made these platforms in batches of about 7 or 8. It would be a fair bit of work to make one on your own. We did it by dividing the tasks up. I did the bent laminations for the sectors, Mark did the electronics. Another member did some of the wood cutting, individual members assembled their own platforms from parts supplied. The assembly took place at a meeting where we could all assist each other.

Rod.