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Open Source Equatorial Mount

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#1 Adam Brunette

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Posted 17 January 2013 - 02:30 PM

Hello Everyone,

This is my first post, but I have been lurking on the forums for some time now. I getting back into astronomer, but have been interested in astronomy for many years.

Anyways, The reason im here is because I have begun designing an open source mount for those of us that like to take the do it yourself approach. I never seem to have enough money for my hobbies, so im always looking for ways to save. One being building a mount for a 12" SCT that I can use for astrophotography. I have alot of experiences with machine design so I thought it would be a good project.

The goal is a mount that can be machined 90% on just a lathe and most of the rest with a drill press. Using this as a guide, I think anybody with a lathe should be able to build one. Im shooting for a capacity of about 70lbs of equipment max or somewhere around there.

Here is a picture of what I have so far.
https://plus.google....977397423256...

Im looking for suggestions to make this as generic as possible. Currently, the mount is adjustable from 0 to 62 degrees. Im not sure if this is enough range, or even too much. Im at 42 so Im not worried about myself. Second thing im wondering about is what a common diameter for the counterweight shaft should be. Currently I designed it for 1-1/8" which is the same as the Losmandy counterweight shaft. Is this a good generic diameter or should it be different?

For some additional information: The large bearings on the RA and DEC are 6.3" diameter. The main tubes are machined from 4" diameter 1/2" wall aluminum round tube. The side supports are made from 5/8" plate aluminum and the base plate as well.

I think that's all I have for now. If Im out of my mind and there is no interest, please tell me. If there is interest, I will work with anybody interested to make the best low cost home built mount available.

-Adam

#2 Thomas Karpf

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Posted 17 January 2013 - 02:47 PM

I'd suggest posting this in the 'ATM' forum, which is the top forum in the 'Equipment' list.

#3 Adam Brunette

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Posted 17 January 2013 - 03:09 PM

Thanks for the suggestion. I will copy it over there.

-Adam

#4 DaveJ

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Posted 17 January 2013 - 05:21 PM

...Second thing im wondering about is what a common diameter for the counterweight shaft should be. Currently I designed it for 1-1/8" which is the same as the Losmandy counterweight shaft.


I think you'd better check the specs on the diameter of the Losmandy counterweight shaft - it's larger than you mention - much closer to 1.25" than 1.125"

#5 mich_al

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Posted 22 January 2013 - 07:33 AM

I've wondered why counterweights aren't compatable with common dumbell weights. They are available cheap at any 'play it again' / Dunhams / second hand sports store.

#6 Adam Brunette

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Posted 22 January 2013 - 08:07 AM

I've wondered why counterweights aren't compatable with common dumbell weights. They are available cheap at any 'play it again' / Dunhams / second hand sports store.


This is a good point...

The common size of lifting weights is a 1" bore. This could be accommodated since the counter weight shaft is threaded and screws onto the back of the back of DEC shaft. The only issue with this is they weights don't individually lock to the shaft.

-Adam

#7 Startraffic

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Posted 22 January 2013 - 08:22 AM

DaveJ,
I thiink the HGM-200 & Titan are even bigger than that. I know my HGM also has a threaded shaft that the CWs thread onto & the toe saver (1/4-20) hole. I'm not positive but mine might be 1.5", I'll check this evening.

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#8 jrcrilly

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Posted 22 January 2013 - 09:48 AM

DaveJ,
I thiink the HGM-200 & Titan are even bigger than that.


The HGM-200 used a 1.5" shaft. The Titan uses 1.25" (weights are interchangeable with the G-11).

#9 Startraffic

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Posted 23 January 2013 - 07:47 AM

John,
I thought it was bigger than the G11. I know it leaves a MUCH bigger lump on my head....every stinkin' time.

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#10 Raginar

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Posted 23 January 2013 - 09:04 AM

How are we going to automate this? :) Retrofit a Gemini system to it? What about an arduino-based control system?

#11 Adam Brunette

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Posted 23 January 2013 - 09:14 AM

How are we going to automate this? :) Retrofit a Gemini system to it? What about an arduino-based control system?


This will have an open source control system based on an embedded processor. There are alot more details in the ATM section. I will update the first post with a link.

-Adam

#12 Adam Brunette

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Posted 23 January 2013 - 09:15 AM

Alright, I cant edit the first post. Here is the link:

http://www.cloudynig...5628274/page...

-Adam

#13 orlyandico

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Posted 23 January 2013 - 11:57 AM

somebody has already written Arduino code that emulates a Synta motor controller. Which means it can be controlled with EQMOD.






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