Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> ATM, Optics and DIY Forum

Pages: 1 | 2 | 3 | (show all)
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Open Source Equatorial Mount
      #5628274 - 01/17/13 03:11 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.com/photos/104884466810529317877/albums/58344977397423256...

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


Post Extras: Print Post   Remind Me!   Notify Moderator  
stmguy
sage


Reged: 10/11/12

Loc: Western NH
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #5628283 - 01/17/13 03:16 PM

I think that is a great project. On the Dec shaft dia , years ago I saw a mount at Stellafane that had a huge diameter Dec shaft which was very short, the reasoning being that that long Dec shafts can act as tuning forks and set up a harmonic which can be hard to track down..who knows ?

I say go for it

Norm


Post Extras: Print Post   Remind Me!   Notify Moderator  
fetoma
Carpal Tunnel
*****

Reged: 09/26/06

Loc: Southern New Jersey
Re: Open Source Equatorial Mount new [Re: stmguy]
      #5628376 - 01/17/13 04:01 PM

Adam,

I am a machinist, and can give you some feedback if you are interested. One thing I recommend is not doing much on the drill press, but rather a milling machine like a Bridgeport. Give me a nice lathe and a Bridgeport with digital readout, and I could make just about anything. Problem is I have neither, nor access to them.

I believe that the capacity will much depend on the internal gears and bearing size. The bigger, the more capacity.

As for the counterweight shaft, I think the Losmandy size would be fine, but if you need something a bit beefier, you can go with the Casady size bar.


Post Extras: Print Post   Remind Me!   Notify Moderator  
hectar
member


Reged: 12/24/12

Loc: Ontario, Canada
Re: Open Source Equatorial Mount new [Re: fetoma]
      #5628482 - 01/17/13 05:09 PM

Adam I do have some CAD experience. your sketch does not shows much details. Could you post actual pictures and full cross sectional drawing with all of dimensions here?? Just curious, where are you located: Nigeria??

Post Extras: Print Post   Remind Me!   Notify Moderator  
Sean Cunneen
Let Me Think
*****

Reged: 08/01/07

Loc: Blue Island Illinois
Re: Open Source Equatorial Mount new [Re: fetoma]
      #5628494 - 01/17/13 05:17 PM

From someone who has built a large mount, the challenges for me were how to drive the axis. Figuring out clutch arrangments for the RA and DEC that would hold and move nicely with a gearing assembly that was easy to make yet strong enough and precision enough for a large scope was very difficult. People who look at my project now have no idea how many renditions or drafts I've built to get to where it is now!

If you check out ATM vol 1, there is a section on mounts and what ingalls says holds true to this day, a telescope mount is only as good as the junctions between the dec axis and the tube as well as the RA and the dec axis. Those two junctions should be your focus. Everyone always gets hung up on the size of the bearings when in reality, mounts move so little bushings are often a better choice. If I could have machined bushings, I would have, but I had to go with bearings myself.

The other "rule" is to keep the counterweight shaft as short as possible and have the OTA as close to the RA shaft as possible.

I am envious of your Computer skills, I have to use "mind-cad"


Post Extras: Print Post   Remind Me!   Notify Moderator  
DaveJ
Carpal Tunnel
*****

Reged: 01/07/05

Loc: NE Ohio
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #5628512 - 01/17/13 05:24 PM

Quote:

...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?




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".


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: fetoma]
      #5628558 - 01/17/13 05:52 PM

Quote:

Adam,

I am a machinist, and can give you some feedback if you are interested. One thing I recommend is not doing much on the drill press, but rather a milling machine like a Bridgeport. Give me a nice lathe and a Bridgeport with digital readout, and I could make just about anything. Problem is I have neither, nor access to them.

I believe that the capacity will much depend on the internal gears and bearing size. The bigger, the more capacity.

As for the counterweight shaft, I think the Losmandy size would be fine, but if you need something a bit beefier, you can go with the Casady size bar.




The plan for the drill press was just for holes. I have a lathe and 2 come converted CNC mills, but I wanted to design something that somebody with a drill press and X-Y table and a lathe would be able to build.

The main end bearings are as big as I could get and still be economical. They are 6218-2RS which have a 160mm outside diameter which is about 6.3". The inside is 90mm. They are sealed and should never need greasing.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: hectar]
      #5628577 - 01/17/13 06:04 PM

Quote:

Adam I do have some CAD experience. your sketch does not shows much details. Could you post actual pictures and full cross sectional drawing with all of dimensions here?? Just curious, where are you located: Nigeria??




I will get some more detailed pictures and cut-aways posted either tonight or tomorrow.

Im in Central Massachusetts in the USA.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
orlyandico
Postmaster
*****

Reged: 08/10/09

Loc: Singapore
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #5628643 - 01/17/13 06:38 PM

I found some neat ideas from looking at the Mach1. The polar fork is not a single-piece casting or anything but several machined billets that are bolted together.

the RA axis is simply a large tube that is bolted to another billet (that is then held in the polar fork).

the mount was obviously designed so that castings are not necessary. I'll try to post some photos of the internals when I get a chance.


Post Extras: Print Post   Remind Me!   Notify Moderator  
ccaissie
professor emeritus


Reged: 09/13/10

Loc: Whitefield, Maine
Re: Open Source Equatorial Mount new [Re: hectar]
      #5629616 - 01/18/13 10:19 AM

Quote:

Just curious, where are you located: Nigeria??



Charlton, MA is not very close to Nigeria, but some of us from Worcester used to think so.
For a project that is designed to be low cost and simple, I'm thinking this is quite sophisticated. I am familiar with the pillow block and plate designs when it comes to simple.

I agree that the broad brush concept is very nice. Details are what make it easy/difficult, and these issues come out in either prototype building or in detail CAD drawings that work out all the clearances, sizes etc. of components. As the details get worked out, please post. I'm interested in producing a nice GEM someday, as I consider a scope finished when I've star tested the optics, and I've got a lot of fine OTA's kicking around.

Love the open source concept. Sharing works.

go man, go!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Startraffic
professor emeritus
*****

Reged: 02/12/06

Loc: Lat. 39.143345, Long. -77.1748...
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #5629892 - 01/18/13 12:45 PM

Adam,
If you want beefy, & simplicity take a look at the Opticcraft mounts. http://www.opticcraft.com/ They use a lot of pillow block bearings & heavy shafts in their designs. The biggest machining issue looks to be the RA & DEC gears. I think they use Byers gears & thrust bearings for the drive mechanisms. I'm not a machinist by any means but their design seems simple, modular & solid.
I'm planning on a 8 or 9 for my 14.5" trailer scope.

Clear Dark Skies
Startraffic
39.138274 -77.168898


Post Extras: Print Post   Remind Me!   Notify Moderator  
ahopp
sage


Reged: 05/24/12

Re: Open Source Equatorial Mount new [Re: Startraffic]
      #5629953 - 01/18/13 01:33 PM

Startraffic, I too have a mobile observatory, 8.5'x23'. Would love to see pictures of your setup and trade notes/experiences.

Tony


Post Extras: Print Post   Remind Me!   Notify Moderator  
hectar
member


Reged: 12/24/12

Loc: Ontario, Canada
Re: Open Source Equatorial Mount new [Re: Startraffic]
      #5629954 - 01/18/13 01:33 PM

RE: ccaissie

I was just curious and I asked him because he didn't mentioned his location until it was asked in my post…(until 4th post)

To be honest, I had similar experience at another forum with a scam artist who had quite good knowledge of the astronomy and he asked me if I could help his sick sister studying at UK and send her some money. (and Nigeria had similar reputation).

Adam's project sounds nice AND If it is "open source" as he mentioned, he must have built it (he says so), lets share it here. Also if it is real, I would sure do my contribution but not by sending him money. Sorry Adam, I hope you are not one of the scam ??(My apology if I am wrong).


I am looking forward to hearing from Adam and knowing his machine design experience as well.
My next question: Is he willing to meet any of us from here and show the real project (and the progress)??

( I would warn everyone to be aware of SCAMS on any forums here at Cloudynights.com ).


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: Sean Cunneen]
      #5629970 - 01/18/13 01:43 PM

Quote:

From someone who has built a large mount, the challenges for me were how to drive the axis. Figuring out clutch arrangments for the RA and DEC that would hold and move nicely with a gearing assembly that was easy to make yet strong enough and precision enough for a large scope was very difficult. People who look at my project now have no idea how many renditions or drafts I've built to get to where it is now!

If you check out ATM vol 1, there is a section on mounts and what ingalls says holds true to this day, a telescope mount is only as good as the junctions between the dec axis and the tube as well as the RA and the dec axis. Those two junctions should be your focus. Everyone always gets hung up on the size of the bearings when in reality, mounts move so little bushings are often a better choice. If I could have machined bushings, I would have, but I had to go with bearings myself.

The other "rule" is to keep the counterweight shaft as short as possible and have the OTA as close to the RA shaft as possible.

I am envious of your Computer skills, I have to use "mind-cad"




Sean,

Thanks for the advice. Im going to find the information you mentioned now.
I chose bearings for a few reasons, One, as you mentioned is they dont need to be machined. Ebay is a good source for mechanical parts I have found over the years.

So you saying make sure the junctions between the the RA and DEC tube as rigid as possible. Im thinking of having the dovetail on the DEC machined right into the end so its as stiff as possible but thats down the road a little.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: DaveJ]
      #5629974 - 01/18/13 01:44 PM

Quote:

Quote:

...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?




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".




Dave,

You are correct, they are 1.25". I have corrected the drawing to reflect this. Thanks!

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: orlyandico]
      #5629983 - 01/18/13 01:48 PM

Quote:

I found some neat ideas from looking at the Mach1. The polar fork is not a single-piece casting or anything but several machined billets that are bolted together.

the RA axis is simply a large tube that is bolted to another billet (that is then held in the polar fork).

the mount was obviously designed so that castings are not necessary. I'll try to post some photos of the internals when I get a chance.




The Mach1 is a very nice mount. I was able to get some ideas from it. Like you mentioned, the DEC tube is mounted to the RA Axis.

I would LOVE to see the insides of one! Right now im stuck deciding on a clutch design.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: hectar]
      #5630023 - 01/18/13 02:18 PM

Quote:

Quote:

Just curious, where are you located: Nigeria??



Charlton, MA is not very close to Nigeria, but some of us from Worcester used to think so.
For a project that is designed to be low cost and simple, I'm thinking this is quite sophisticated. I am familiar with the pillow block and plate designs when it comes to simple.

I agree that the broad brush concept is very nice. Details are what make it easy/difficult, and these issues come out in either prototype building or in detail CAD drawings that work out all the clearances, sizes etc. of components. As the details get worked out, please post. I'm interested in producing a nice GEM someday, as I consider a scope finished when I've star tested the optics, and I've got a lot of fine OTA's kicking around.

Love the open source concept. Sharing works.

go man, go!




HA! A local! Well, What looks like use to be.

Im not sure it will be "Simple" but it will defiantly be as low as cost as possible and very sophisticated.

I use a program called Solidworks to do my designs in. It is a full 3D cad program that has fancy features like interference detection and structural analysis. I dont usually have issues with a design when I finally build it as Ive already found and designed them out in software.

My logic with this project is as follows: I have no want to manufacturer mounts. I simply don't have time. I do feel like others can benefit from my designs and some people will be able to build it if they want to.

Quote:

Adam,
If you want beefy, & simplicity take a look at the Opticcraft mounts. http://www.opticcraft.com/ They use a lot of pillow block bearings & heavy shafts in their designs. The biggest machining issue looks to be the RA & DEC gears. I think they use Byers gears & thrust bearings for the drive mechanisms. I'm not a machinist by any means but their design seems simple, modular & solid.
I'm planning on a 8 or 9 for my 14.5" trailer scope.

Clear Dark Skies
Startraffic
39.138274 -77.168898




Startraffic,

I will take a look at what they make.

As of right now, the hardest part to make is the RA and DEC gears. They have to be super accurate. I have been looking into other options from my other machine design experiences, but I don't think I can come up with anything in the same cost range.

Quote:

RE: ccaissie

I was just curious and I asked him because he didn't mentioned his location until it was asked in my post…(until 4th post)

To be honest, I had similar experience at another forum with a scam artist who had quite good knowledge of the astronomy and he asked me if I could help his sick sister studying at UK and send her some money. (and Nigeria had similar reputation).

Adam's project sounds nice AND If it is "open source" as he mentioned, he must have built it (he says so), lets share it here. Also if it is real, I would sure do my contribution but not by sending him money. Sorry Adam, I hope you are not one of the scam ??(My apology if I am wrong).


I am looking forward to hearing from Adam and knowing his machine design experience as well.
My next question: Is he willing to meet any of us from here and show the real project (and the progress)??

( I would warn everyone to be aware of SCAMS on any forums here at Cloudynights.com ).




ccaissie,

I understand your concern as I am a long time traveler of many different forums.

Since you post, I updated my profile to reflect my information.

To clear up a few little details though. The project will be released as Open Source when completed. (or sooner if somebody comes to me directly) I have no built the mount yet, as Im still in the design phase. I wanted to get opinions before I designed something people didn't like.

I dont take offense to your caution of scam potential. I would be cautious too if it happened to me.

Yes, I am willing to show the real thing to people when that time comes. Like I said, it is just in the computer right now.

And to finish up all these reply's, Here is some of the stuff I've built before.

Time lapse camera panner:
I designed this to hold very large cameras to do time lapse work. It is capable of rotating over 200lbs and can do so with 8400 steps of rotation per revolution. Unit runs from a 12V battery pack for cameras. http://www.flickr.com/photos/adambrunette/sets/72157626111606853/

And a video:http://www.youtube.com/watch?v=iUJx6F_MnxA
And one of the milling machine I converted to CNC machining the top housing of the panner: http://www.youtube.com/watch?v=UL8_wRSTzXs

And a shot of the little machine :http://www.flickr.com/photos/adambrunette/4737054165/in/set-72157624365713534/

I have done so many projects I cant list them all, But check out my you tube channel for a good overview including machine building, My golf cart, My electric Corvette, robotics and others. http://www.youtube.com/user/Adamj12b?feature=mhee

phew...done for now. I will post more pics of the GEM later.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
hectar
member


Reged: 12/24/12

Loc: Ontario, Canada
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #5630347 - 01/18/13 06:14 PM

Adam you look quite resourceful and if it can be done, your name will be written in the history books of the astronomy just like Dr. Craig Stark who wrote world's best and free guiding program called PHD!!!

I would suggest following:

1. Declare it officially as an open source hardware project…
How/should this declared officially, so all of us here will be legally/morally bound to it? Could someone provide declaration/suggestions or more information about this?? We need help…
Btw I did find
http://www.youtube.com/watch?v=9xGRaPrcvVg
By http://www.oshwa.org/
What every one thinks about this??
I personally think it is needed as there will be everyone's time and efforts involved. We must be honest and fair. We should honor what we say or declare.
(I would hate to see it stolen by the companies who are already making 300% or more profit, preying on people’s dreams and producing cheap/raw castings)

2. Come up with a plan. I.e. what are the sources of requirements for this project?? What is needed?. How it should be done etc..
I would say, we should start with a manual equatorial mount that will be capable of becoming an automated one. How strong, how much load, we will find out.

3. I am well aware what SW can do/ or what it’s capable of…We all will discuss what parts will be required and how they should work etc and then build them part by part. Then do the final assembly, run the simulation/FEA, which will point out itself where improvements/modifications are needed…

4. As we go along, you post videos and pictures of the progress here, at your YouTube channel and flicker account.

5. Once the design is complete/perfect, Most of us will manufacture it or get it manufacture at machine shop. Do the test and trials etc..

6. Next step will be to automate it and modify design for motors/controllers to run it and so on…(if needed)

7. Etc...Any suggestions??

PS: I am still awaiting dimensional drawing you were supposed to post here...


Post Extras: Print Post   Remind Me!   Notify Moderator  
skywolf856
sage


Reged: 01/25/08

Loc: SE Michigan
Re: Open Source Equatorial Mount new [Re: hectar]
      #5630498 - 01/18/13 07:51 PM Attachment (61 downloads)

I think the Opticcraft mounts are the easiest design to duplicate with minimum machining capabilities required.

Here is my version with a 1 5/8" polar shaft and 1" dec shaft running in pillow blocks.

The clock drive is mine too! Designed using Stock Drive gearing products off the shelf using a Hurst 1 rpm syncro motor.


Post Extras: Print Post   Remind Me!   Notify Moderator  
skywolf856
sage


Reged: 01/25/08

Loc: SE Michigan
Re: Open Source Equatorial Mount new [Re: skywolf856]
      #5630500 - 01/18/13 07:53 PM Attachment (52 downloads)

Here is my homemade clock drive.

Post Extras: Print Post   Remind Me!   Notify Moderator  
orlyandico
Postmaster
*****

Reged: 08/10/09

Loc: Singapore
Re: Open Source Equatorial Mount new [Re: skywolf856]
      #5631565 - 01/19/13 01:21 PM

you can get the gears from Aeroquest:

http://www.aeroquest-machining.com/pricing.php

smaller one for the DEC. or, if goto is not necessary, use a tangent-arm DEC. it would be simpler, cheaper, and suffer less from backlash and stiction.

i would vote for a Raspberry Pi (or Chipkit32 Arduino) for the Goto controller, if Goto is desired.

the 10 Micron mounts use an embedded Linux SBC, not the cheesy low-RAM microcontrollers that are generally used in mounts.


Post Extras: Print Post   Remind Me!   Notify Moderator  
BoriSpider
Carpal Tunnel


Reged: 08/10/04

Loc: S.W.FLA
Re: Open Source Equatorial Mount new [Re: orlyandico]
      #5633021 - 01/20/13 11:25 AM

I should know a little about the OpenSource licensing since I
follow alot of OS projects, but I don't. Adam can join the G+
community "Makers, hackers, artists, engineers" community run
by adafruit.com and get the answers there.

I like this open source astro equipment trend. I have(just got)
a 3d printer. If the cad files are in a Blender friendly format
I can get them to my printer and print them to see how they fit together.
If the files can be exported to a '.stl' file, even better. If proto-typing in plastic will help I can be of
service.


Post Extras: Print Post   Remind Me!   Notify Moderator  
hectar
member


Reged: 12/24/12

Loc: Ontario, Canada
Re: Open Source Equatorial Mount new [Re: BoriSpider]
      #5633072 - 01/20/13 12:09 PM

Quote:

I should know a little about the OpenSource licensing since I
follow alot of OS projects, but I don't. Adam can join the G+
community "Makers, hackers, artists, engineers" community run
by adafruit.com and get the answers there.

I like this open source astro equipment trend. I have(just got)
a 3d printer. If the cad files are in a Blender friendly format
I can get them to my printer and print them to see how they fit together.
If the files can be exported to a '.stl' file, even better. If proto-typing in plastic will help I can be of
service.




Me too!. "3d printer" which is kinda misleading term, is actullay a full manufacturing device; I dont have yet, but I am planning to get one. They are great for building proto-type parts.


Post Extras: Print Post   Remind Me!   Notify Moderator  
ccaissie
professor emeritus


Reged: 09/13/10

Loc: Whitefield, Maine
Re: Open Source Equatorial Mount new [Re: hectar]
      #5633319 - 01/20/13 02:19 PM Attachment (40 downloads)

A lot of nice looking work can be done using pipe fittings bored to suit bearing inserts etc. Clearly you want to get past the "sawmill" look on your mount.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Startraffic
professor emeritus
*****

Reged: 02/12/06

Loc: Lat. 39.143345, Long. -77.1748...
Re: Open Source Equatorial Mount new [Re: ahopp]
      #5634425 - 01/21/13 07:21 AM

Tony,
I've actually got 2 trailers underway. One is a stock 16ft beavertail twin axle car trailer that I got for moving my tractor with. The other is a purpose built 9ftx16ft dual axle trailer for a 14.5f30 Shiefspeigler Bino obs. I just got the plans approved by MD Motor Vehicle Administration (after 4 yrs of design work!) & the construction/welding jig built. I haven't done much more than gather steel & axles yet. & I'm still guessing that the Opticcraft 8-9 will hold the scope. The scope & mirrors haven't been built yet.

Clear Dark Skies
Startraffic
39.138274 -77.168898

Edited by Startraffic (01/21/13 11:32 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: ccaissie]
      #5634773 - 01/21/13 11:41 AM

Quote:

you can get the gears from Aeroquest:

http://www.aeroquest-machining.com/pricing.php

smaller one for the DEC. or, if goto is not necessary, use a tangent-arm DEC. it would be simpler, cheaper, and suffer less from backlash and stiction.

i would vote for a Raspberry Pi (or Chipkit32 Arduino) for the Goto controller, if Goto is desired.

the 10 Micron mounts use an embedded Linux SBC, not the cheesy low-RAM microcontrollers that are generally used in mounts.




Hello orlyandico,

Those are some nice gears!! Looks like top quality machining. I will keep them in mind, but they are super expensive.

This will be a GOTO mount.

The electronics will be AVR based which will make it Arduino compatible. My actual passion and schooling is electronic design. Machining and engineering is just a hobby.

This little guy I built a few months ago for work is a hand held network tester and cable checker complete with 2.4" color touchscreen: https://lh4.googleusercontent.com/-RIAzV510C8Q/ULts6l3hUJI/AAAAAAAAF3s/nhOLF8...
https://lh4.googleusercontent.com/-QVrQ1Gw6FI8/ULtsVaUQEEI/AAAAAAAAF28/nwWoxE...

Quote:

I should know a little about the OpenSource licensing since I
follow alot of OS projects, but I don't. Adam can join the G+
community "Makers, hackers, artists, engineers" community run
by adafruit.com and get the answers there.

I like this open source astro equipment trend. I have(just got)
a 3d printer. If the cad files are in a Blender friendly format
I can get them to my printer and print them to see how they fit together.
If the files can be exported to a '.stl' file, even better. If proto-typing in plastic will help I can be of
service.




BoriSpider,

YES!! all the files can be exported in numerous 3D formats. When the time comes, this might be an excellent way of building prototype pieces instead of aluminum!

Quote:

A lot of nice looking work can be done using pipe fittings bored to suit bearing inserts etc. Clearly you want to get past the "sawmill" look on your mount.




ccaissie,

That is a great idea! I will keep it in mind for a smaller project. This one Im sticking with pieces designed for the mount specifically and easy machining on a lathe.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #5634847 - 01/21/13 12:22 PM

Alright, Sorry for the delay on the cutaway and dimensions.

First, the cutaway:
https://lh6.googleusercontent.com/-75FhZ3YBJAY/UP1waxVB8qI/AAAAAAAAHa0/JjdttC...

As you can see, The gear end of the 2 axes are supported by 6218-2rs deep groove bearings. At the far end of the housing, there is another bearing with a bearing pre-load nut. This is tightened down to take all the backlash out of the bearings and provide a fluid axis. The RA axis will be set up the same way.

You can see at the top of the DEC that I have been playing with a clutch design. This is based on the clutch in the Losmandy G11. The tan layer is a piece of cork used as a slip/friction surface for the clutch pad. This would have a secondary shaft through the center of the main shaft and a hand wheel on the end to adjust clutch tension. The thing that worries me is if the end plate and shaft are not rigid enough, they could flex when the clutch is loose and cause inaccuracy. I think bushings would be sufficient for holding the clutch shaft concentric with the axis shaft.

If this is acceptable, I will replicate it on the RA axis.

Here is a rough dimensional drawing. The ones marked "True" are radiuses.

All measurements are in Inch's.

https://lh5.googleusercontent.com/-Vo9XJry7Sek/UP1wbI-xfNI/AAAAAAAAHa4/EaOkyF...


Im still looking for suggestions on the range of latitude the mount should be capable of.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
ahopp
sage


Reged: 05/24/12

Re: Open Source Equatorial Mount new [Re: Startraffic]
      #5635039 - 01/21/13 02:04 PM

Mine has an 8.5' by 10' observing room, retractible fabric roof. The front has an 8.5'x10' plus v-nose, for computer room and living quarters. I use a 3K Honda generator with a 200 AH battery for power. Custom 12vDC control panel to power all the gear. A/C plus baseboard and gas heat.

Tony


Post Extras: Print Post   Remind Me!   Notify Moderator  
BoriSpider
Carpal Tunnel


Reged: 08/10/04

Loc: S.W.FLA
Re: Open Source Equatorial Mount new [Re: ahopp]
      #5635439 - 01/21/13 05:48 PM

Looking good so far Adam. I love the 'lil tester/checker thing.

Post Extras: Print Post   Remind Me!   Notify Moderator  
neo
Carpal Tunnel
*****

Reged: 02/12/08

Loc: Iasi, Romania
Re: Open Source Equatorial Mount new [Re: BoriSpider]
      #5636279 - 01/22/13 06:20 AM

Nice design Adam!
How do you plan to mount the worm gears on the shafts( if that is what you are going to use)?
It would be a good idea though to use roller bearings instead of ball bearings for a better precision and as a sophistication you could use taper roller bearings on the back end of the shaft, especially if you want to go with the preloading idea. Also it would be a more efficient way to deal with the axial and radial forces when the mount points in different positions. I believe Takahashi uses this set up in their mounts.
If you want to go Losmandy way then you should consider mounting the worm wheel on a bearing on the Ra (or DEC) housing itself making it independent to the shaft and avoid the small errors due to flexing or bearing runout. The most important thing I see with this set up is that the worm and worm wheel keep the same contact which will help accuracy. In this way the shaft is driven only by the friction between the worm wheel and the flange of the shaft.
http://www.astro.uni-bonn.de/~mischa/mounts/g11_experiences.html

http://www.astromaster.org/esperienze_file/G11maintenance_e.htm

Here's also a new ukrainian series of mounts using pretty much the same design with very good accuracy, not very hard to build on a lathe.
http://www.youtube.com/user/WhiteSwan180/videos?flow=grid&view=0


Post Extras: Print Post   Remind Me!   Notify Moderator  
m. allan noah
scholastic sledgehammer


Reged: 08/14/09

Loc: Virginia, USA
Re: Open Source Equatorial Mount new [Re: neo]
      #5636379 - 01/22/13 08:24 AM

You need to add a flange or washer that covers the seals on the exposed side of the bearings. Eventually during transport, one of those will get hit and damaged.

allan


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: neo]
      #5636608 - 01/22/13 10:34 AM

Quote:

Nice design Adam!
How do you plan to mount the worm gears on the shafts( if that is what you are going to use)?
It would be a good idea though to use roller bearings instead of ball bearings for a better precision and as a sophistication you could use taper roller bearings on the back end of the shaft, especially if you want to go with the preloading idea. Also it would be a more efficient way to deal with the axial and radial forces when the mount points in different positions. I believe Takahashi uses this set up in their mounts.
If you want to go Losmandy way then you should consider mounting the worm wheel on a bearing on the Ra (or DEC) housing itself making it independent to the shaft and avoid the small errors due to flexing or bearing runout. The most important thing I see with this set up is that the worm and worm wheel keep the same contact which will help accuracy. In this way the shaft is driven only by the friction between the worm wheel and the flange of the shaft.
http://www.astro.uni-bonn.de/~mischa/mounts/g11_experiences.html

http://www.astromaster.org/esperienze_file/G11maintenance_e.htm

Here's also a new ukrainian series of mounts using pretty much the same design with very good accuracy, not very hard to build on a lathe.
http://www.youtube.com/user/WhiteSwan180/videos?flow=grid&view=0




The large cylinder that mounts on the large bearing is to be the worm gear.

Taper bearings are better for preloading, but with every advantage comes drawbacks. Taper bearings are never sealed units (that I have seen). This means measures have to be taken to hold the grease in the bearings.

One major issue to overcome in the homemade/diy category is in order to use needle and direct roller bearings is the shafts need to be hardened and ground as they serve as the inner race. Without this, you will have very poor results. From my past research, it is perfectly acceptable to preload deep groove bearings. A common preload for these is about 4 percent. 5% is 300lbs of preload.

Thanks for the links. Lots of good breakdown pictures to look at.

The Ukrainian mounts are really nice! They look very well built. I cant understand anything they are saying, but I can tell they have has the shafts of the axes hardened and ground. In the 240 mount I made out what I think is cork for the friction pad between the RA gear and end mount.

Quote:

You need to add a flange or washer that covers the seals on the exposed side of the bearings. Eventually during transport, one of those will get hit and damaged.

allan




Allan,

The small end of each axis will be covered by the knob that tightens the clutch. The large bearing will need some kind of cover, but this will also serve as a gear cover.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #5637096 - 01/22/13 02:58 PM

Does anybody know if the diameter and thread of polar scopes for aligning a mount are a common size? I was looking at some of the Celestron ones, but they don't have any measurement, They just say that they fit X mount.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
hectar
member


Reged: 12/24/12

Loc: Ontario, Canada
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #5637483 - 01/22/13 06:14 PM

Quote:

Alright, Sorry for the delay on the cutaway and dimensions.

First, the cutaway:
https://lh6.googleusercontent.com/-75FhZ3YBJAY/UP1waxVB8qI/AAAAAAAAHa0/JjdttC...

As you can see, The gear end of the 2 axes are supported by 6218-2rs deep groove bearings. At the far end of the housing, there is another bearing with a bearing pre-load nut. This is tightened down to take all the backlash out of the bearings and provide a fluid axis. The RA axis will be set up the same way.

You can see at the top of the DEC that I have been playing with a clutch design. This is based on the clutch in the Losmandy G11. The tan layer is a piece of cork used as a slip/friction surface for the clutch pad. This would have a secondary shaft through the center of the main shaft and a hand wheel on the end to adjust clutch tension. The thing that worries me is if the end plate and shaft are not rigid enough, they could flex when the clutch is loose and cause inaccuracy. I think bushings would be sufficient for holding the clutch shaft concentric with the axis shaft.

If this is acceptable, I will replicate it on the RA axis.

Here is a rough dimensional drawing. The ones marked "True" are radiuses.

All measurements are in Inch's.

https://lh5.googleusercontent.com/-Vo9XJry7Sek/UP1wbI-xfNI/AAAAAAAAHa4/EaOkyF...


Im still looking for suggestions on the range of latitude the mount should be capable of.

-Adam




Adam,
I am trying to figure out your design. when designing with two bearings, one end is always "locked". ie one bearing should be: #1. locked on the shaft (ie it's inner race locked with a nut) , and, #2. Locked with in the casing. i.e. Its' outer race locked "with in the casing/housing" by means of a cap, leaving only 0.001-0.003" clearance for the thermal expansion of the bearing race itself.
Now, the other (2nd) end/bearing would be be still in the casing and bearing cap should be there but it will not be locked. it would have rather 0.032 to 0.125 or more gap between the outer race and cap.(Gap is necessary for the thermal expansion of the shaft in the axial direction)

Your design has lock nut in the bottom (so inner race is locked up against the shaft shoulder but outer race is not locked (no bearing cap there), what will stop it from falling? which way it expand due to heat or cold?? it also raises the question how/which order you will install those two 6218-2RS bearings.

In my opinion, 6218-2RS is not a thrust bearing. It is rather just a radial bearing. ( single row deep groove ball bearing with two seals )(suffix RS ). (Although, it can be used as a hobby project, but it wont be a perfect design).
Also, are you suggesting preloading it by the nut to somehow eliminate the bearing's own internal clearance?
I am thinking about posting a sketch here, but I would wait: what you and others think about this?
Btw, lattitude could be 0-90 degrees. if you end up with 70-80, it's ok

Hectar


Post Extras: Print Post   Remind Me!   Notify Moderator  
hectar
member


Reged: 12/24/12

Loc: Ontario, Canada
Re: Open Source Equatorial Mount new [Re: neo]
      #5637498 - 01/22/13 06:23 PM

Quote:

Nice design Adam!
How do you plan to mount the worm gears on the shafts( if that is what you are going to use)?
It would be a good idea though to use roller bearings instead of ball bearings for a better precision and as a sophistication you could use taper roller bearings on the back end of the shaft, especially if you want to go with the preloading idea. Also it would be a more efficient way to deal with the axial and radial forces when the mount points in different positions. I believe Takahashi uses this set up in their mounts.
If you want to go Losmandy way then you should consider mounting the worm wheel on a bearing on the Ra (or DEC) housing itself making it independent to the shaft and avoid the small errors due to flexing or bearing runout. The most important thing I see with this set up is that the worm and worm wheel keep the same contact which will help accuracy. In this way the shaft is driven only by the friction between the worm wheel and the flange of the shaft.
http://www.astro.uni-bonn.de/~mischa/mounts/g11_experiences.html

http://www.astromaster.org/esperienze_file/G11maintenance_e.htm

Here's also a new ukrainian series of mounts using pretty much the same design with very good accuracy, not very hard to build on a lathe.
http://www.youtube.com/user/WhiteSwan180/videos?flow=grid&view=0



I like your idea better. If someone can translate video, it would be great.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: hectar]
      #5637652 - 01/22/13 08:14 PM

Hectar,

Some gaps and reliefs need to be updated. I have done extensive work on the design today, and hope to post a new picture some time tonight. I think it will clear up some questions.

I understand about the bearing concern. The 7218 angular contact ball bearing is a direct fit for the deep groove bearing, but the cost is alot higher. It is a good fit for the task though. There is also the 30218 which is a taper roller bearing.

There are options for the far end bearing as well. The part I don't like still is these type bearings need lubrication.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
m. allan noah
scholastic sledgehammer


Reged: 08/14/09

Loc: Virginia, USA
Re: Open Source Equatorial Mount new [Re: hectar]
      #5637665 - 01/22/13 08:21 PM

Quote:


In my opinion, 6218-2RS is not a thrust bearing. It is rather just a radial bearing. ( single row deep groove ball bearing with two seals )(suffix RS ). (Although, it can be used as a hobby project, but it wont be a perfect design).
Also, are you suggesting preloading it by the nut to somehow eliminate the bearing's own internal clearance?





Don't get caught up in the name 'thrust' vs 'radial' a deep groove ball bearing is not all that far removed from an angular contact bearing. I routinely use them in this type of service with a bit of preload.

However, I would say that the 6218 is really much bigger than needed. In fact, I would be inclined to forgo the rolling bearing entirely on the big end of each axis. I am partial to something more like the Discmount uses, either a disk or a cone of plane bearing.

allan

Edited by m. allan noah (01/22/13 08:23 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
m. allan noah
scholastic sledgehammer


Reged: 08/14/09

Loc: Virginia, USA
Re: Open Source Equatorial Mount new [Re: m. allan noah]
      #5637738 - 01/22/13 08:55 PM

Oh, and perhaps this will be of some use to you:

http://translate.googleusercontent.com/translate_c?client=firefox-a&depth...


Post Extras: Print Post   Remind Me!   Notify Moderator  
hectar
member


Reged: 12/24/12

Loc: Ontario, Canada
Re: Open Source Equatorial Mount new [Re: m. allan noah]
      #5637812 - 01/22/13 09:29 PM

Re: 6218-2RS, I almost forgot the cost. since they can take some axial load in both directions, they may be ok.
Adam, you could use/accomodate a cheap automotive lip seal at either one/both bearing caps, which would contain the grease, thus allowing you to use roller/taper/cone bearing at one end. They do come with both races (as suggested above as well). You have to search for a cheaper one though.

Thanks for posting link Allan.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: hectar]
      #5637870 - 01/22/13 10:15 PM

Allan,

Do you have an example of this Diskmount method?

I still think the 6218-2rs is be best low cost solution. It will never spin more then 1 RPM. They can be had new on ebay for $30 each. Im thinking I will start with these bearings and if they are not up to the job, there are 2 other options that are a direct fit.

Thanks for the link to that! Im looking through it now.

Hectar,

That's a good idea about the lip seals. I never thought of those.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #5638032 - 01/22/13 11:42 PM

Alright, As I promised, here is an updated cut away view. This is incorporating the cork friction disks I mentioned earlier on. RA shaft is hollow to accept a polar scope. Counterweight shaft screws into the DEC shaft for modular approach.

Next part I plan to work on is the fork mount and base.

Enjoy!



Link for full rez version. https://docs.google.com/file/d/0B_sezR3BZVeIYXUtS0Z4Ykhpdjg/edit

-Adam

Edited by Adam Brunette (01/22/13 11:47 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
orlyandico
Postmaster
*****

Reged: 08/10/09

Loc: Singapore
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #5638155 - 01/23/13 01:15 AM

sounds like it will need a lathe to build...

this is the cheapest source of gears I've seen...
http://www.gototelescopes.com/gears.htm

although Edward Byers (seller ID erbyers on ebay) sometimes sells his fabulous gears on ebay. They are more expensive than the Aeroquest gears though.. but are a known good quantity. The earliest Paramount GT mounts used Byers gears.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Startraffic
professor emeritus
*****

Reged: 02/12/06

Loc: Lat. 39.143345, Long. -77.1748...
Re: Open Source Equatorial Mount new [Re: ahopp]
      #5638311 - 01/23/13 06:56 AM

Ahopp,
Mine will be a 8'x16' bumper pull Obs with a 1kw gen, solar & batteries. The mount will be lowered through the floor to sit in the ground & isolated from the trailer which will be raised on jacks to level. It'll make for a nice stable portable obs. The 8' dome will be either a Skyshed POD or an automated 8' Home dome & will be towards the front of the trailer for balance & ease of mount operation. The electrical will be towards the back to counterbalance the dome, mount & scope. I hope to have a small warm room on the back but I haven't figured that out yet. I don't want to hijack this thread any further though.

Clear Dark Skies
Startraffic
39.138274 -77.168898


Post Extras: Print Post   Remind Me!   Notify Moderator  
neo
Carpal Tunnel
*****

Reged: 02/12/08

Loc: Iasi, Romania
Re: Open Source Equatorial Mount new [Re: m. allan noah]
      #5638348 - 01/23/13 07:46 AM

Quote:

Oh, and perhaps this will be of some use to you:

http://translate.googleusercontent.com/translate_c?client=firefox-a&depth...




I like that for a home made mount!
That's basically the same setup used in the WS mounts in the Youtube videos, and what I was on about although the author used only needle bearings.

Adam you are right about the needle bearings but you can get ones which already have the inner and outer racers. Check the Timken catalog. I can't find the link right now

By the way very ingenious design, now that I see it more complete! But you have to admit it's not going to be easy to build without proper tooling. Al the shafts would need high precision machining to get good coaxiality.
Also, I'm not sure I might be wrong, but it looks like the worm wheels will take quite a bit of load, the outer/inner axles resting directly on them. Probably this could be much better judjed with a 'live' prototype and see how it tracks.
All in all a very good effort and quite different design from what most of us are used to, so can't wait for further refinements


Post Extras: Print Post   Remind Me!   Notify Moderator  
m. allan noah
scholastic sledgehammer


Reged: 08/14/09

Loc: Virginia, USA
Re: Open Source Equatorial Mount new [Re: neo]
      #5638399 - 01/23/13 08:30 AM

It appears that you want to use the worm wheel as the container for the outer race. In use, there will be some outward force from the bearing. I think your thin-walled gear will be harder to make, and more likely to distort in that situation. I think you need to consider making the design more adaptable to gears from different sources, since that is the most likely highest cost component. Builders might want to scrounge a little, or might already own a gearset from another mount.

allan


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: m. allan noah]
      #6023290 - 08/13/13 03:48 PM

Hello Everyone,

It has been awhile since I have posted anything related to this. However, This does not mean progress has stopped on it!

Allen's last post got me thinking and I decided to change a few things.

I have redesigned how the gears mount to the upper bearings. Instead of being cut with the axis hub, they will be separate gears, loc-tight'ed to the bearing. The hub will also be loc-tight'ed to the bearing. This allows anybody with a large enough gear to bore to 160mm (6.299") can fit them to the mount.

In the past few months, I have been sourcing parts to build the mount. I happened to get the chance to get a set of 9" Byers gears and worms directly from Ed Byers. I talked to him on the phone a few times and he said he retired 2 years ago and was just selling off his left over inventory. He does not have much left now and what is left is on his Ebay page.

Anyways, I was able to get 2 sets of 9" gears with worms mounted on 2 bearing blocks with custom bore for $650. While this is more then I wanted to spend on gears, I could not pass up the opportunity of using Byers gears in my mount.

I have mostly made refinements to the design I posted a few months ago. Shafts the main shafts of each axis is a standard diameter for linear bearing rails. These are very accurate in roundness and also are usually chrome plated. This is perfect for needle roller bearings. The RA clutch shaft is 40mm OD with a 22mm ID. This allows some amount of cables to pass through the RA. Its better then nothing I guess.

The azimuth adjustment is done with 2 precision set screws. These are 2" long and have 80 threads per inch. The push against a block in the base to twist the mount. When your in position, there is 6 locking levers that clamp the base plate with the azimuth plate. These levers are re-position-able so once locked, you can release them and rotate them out of the way. There is +/- 7.5 degrees of azimuth adjustment.

The altitude has been modified a good bit from the original design. The adjustment screw is also a 80 thread setscrew allowing for super accurate adjustments. The block that mounts the set screw is adjustable to 4 positions. The altitude ranges are 10-25, 25 - 40, 40-55, 55-70. I'm in the middle at 42 degrees. The main pivot of the RA axis is on 2 - 3/8" shoulder bolts, and is locked in place with 2.25" 5 lobe knobs.

The biggest changes are the gear box's / gear covers. The lower half of the gear cover is actually the structural mount of the worm gear and servo mount. These are probably some of the most expensive pieces of aluminum. Its about $360 for all the material for both of the gear box's. The lower part of the gear box is 1.5" thick milled to a shell with a 1/2" bottom. Its alot of material to remove, but no real better way to accomplish a tight cover that looks good. The lower cover is bored to fit nicely around the main tube of the axis and is secured to a mounting ring with 5 - 5/16 stainless steel bolts in a circle pattern. The mounting ring is also machined to fit the main tube snugly and is secured to the tube with 5 more 5/16 bolts. Both axes are set up this way.

The upper gear cover is also milled from solid aluminum with a whole bored to fit the hub of the axis. The hub rids on the main bearing. The worm wheel is loc-tighted to the bearing and secured to the hub with 5 screws.

Half of the upper cover is removable to allow easy access to the worm gear and servo components.

The worm gear and servo are mounted on a common pivot point and are held down with shoulder screws. This allows the whole worm/servo block to pivot to maintain constant pressure of engagement between the worm gear and wheel. This pressure is applied with 2 set screws with springs. These are accessible from outside of the gear casing.

The counter weight shaft is an off the shelf piece from Astro Phsyics. It is a 1.875" shaft. I liked the look of the shaft and counter weights and wanted to use these. The shaft can be re sized easily as long as it can thread into the DEC tube.

The mount can be taken apart at the intersection of the RA and DEC for easier transport. If wanted, the RA tube can be removed from the support arms by removing the 2 hand knobs and the 2 shoulder bolts. This would break it into 3 sections roughly about 30lbs each.

Here is a few older renders of the mount with a model of my Meade LX200 12" EMC on it as well as 2 - 18lb counter weights.

I have begun building this now and will post what I have done.

-Adam

Mount minus counter weight shaft:
https://lh3.googleusercontent.com/-x5xFO0elZE0/Ugp9WF4snCI/AAAAAAAAM-M/2f1rPc...

Base of mount:
https://lh4.googleusercontent.com/-AZRvAbH85FU/Ugp9W6s2H3I/AAAAAAAAM-U/7EoGVD...

Meade 12" Tracking:
https://lh3.googleusercontent.com/-zh23pPszEpA/UdQRc163ZWI/AAAAAAAALuc/1YRRsl...

Meade 12" almost home:
https://lh4.googleusercontent.com/-xkH3oCzbzII/UdQRedbCG7I/AAAAAAAALuo/r6nr9Z...


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #6023324 - 08/13/13 04:04 PM

Here is a link to the latest render that just finished. You can see the servo/worm gear mount on the DEC axis.

https://lh5.googleusercontent.com/-38KHu1Rt1hY/UgqQetect7I/AAAAAAAAM-w/duSZZN...


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pinbout
Postmaster
*****

Reged: 02/22/10

Loc: nj
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #6023695 - 08/13/13 06:33 PM

again this is open source atm'ing

I see your very nice renderings, but I haven't seen access to your model.

and strock puts up a pdf of the cut parts and hand drawings for open source


Post Extras: Print Post   Remind Me!   Notify Moderator  
BoriSpider
Carpal Tunnel


Reged: 08/10/04

Loc: S.W.FLA
Re: Open Source Equatorial Mount new [Re: Pinbout]
      #6024833 - 08/14/13 10:44 AM

Yes, access to the models would be nice. That way others can contribute.
You can always put them up on thingiverse.com or Thingtracker which is a github.com based deal(since MakerBot is no longer open-source-ish).


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: BoriSpider]
      #6024853 - 08/14/13 10:55 AM

Can do! I will look into it. Currently it is in Solidworks.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pinbout
Postmaster
*****

Reged: 02/22/10

Loc: nj
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #6024903 - 08/14/13 11:31 AM

put it in sketchup

http://www.javelin-tech.com/blog/2011/03/export-sw-to-sketchup/


Post Extras: Print Post   Remind Me!   Notify Moderator  
jhayes_tucson
professor emeritus
*****

Reged: 08/26/12

Loc: Bend, OR
Re: Open Source Equatorial Mount new [Re: Adam Brunette]
      #6025141 - 08/14/13 01:30 PM

After taking a quick look at your design, I'll give you a few things to think about: You can get better load capability (both radial and axial) and zero out backlash by using tapered roller bearings. They need a preload, which can be done with a threaded nut bearing on the inner race along the axis. Shaft stiffness becomes a little more important but you want to pay attention to that anyway so you should look at the effect of hollow shafts on bending moments and torsional rigidity. In any case, you are wise to incorporate some way to add and control friction for each axis. With any kind of roller bearing, the motion will be way too smooth to balance without friction control. I believe that you are better off putting a mounting boss on the RA axis for a small alignment scope. Mount it with alignment pins and a quick release so that it can be easily removed. Putting a hole through the Dec axis to accommodate an alignment system isn't that good for rigidity; though it helps with weight. Finally, where do you put drives on this design?

John


Post Extras: Print Post   Remind Me!   Notify Moderator  
m. allan noah
scholastic sledgehammer


Reged: 08/14/09

Loc: Virginia, USA
Re: Open Source Equatorial Mount new [Re: jhayes_tucson]
      #6033178 - 08/18/13 04:39 PM

All these renderings just show us the same info over and over again. We all know what the outside of a black GEM looks like

We need a cutaway view to help you develop the idea further.

allan


Post Extras: Print Post   Remind Me!   Notify Moderator  
Adam Brunette
member


Reged: 01/13/13

Loc: Charlton, Massachusetts
Re: Open Source Equatorial Mount new [Re: m. allan noah]
      #6035555 - 08/19/13 10:57 PM

Hello Allan,

I generated this one a few days ago, but didnt get a chance to post it yet.


And a high rez iso sectional:
https://lh3.googleusercontent.com/-iOrZhxi8dLE/UhLYnA5htQI/AAAAAAAANIo/RL8upk...

The yellow rectangle with the notch is the worm wheel and the gold block with circle touching the worm wheel is the worm gear and mounting block. The grey block next to the worm block is the worm /servo mount.

The needle roller bearings are not shown on either axis so use your imagination where the cutouts are on the axis bearing preload shaft. The shaft inside the axis shaft is the clutch shaft for tightening the clutch.

-Adam


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | (show all)


Extra information
9 registered and 26 anonymous users are browsing this forum.

Moderator:  ausastronomer, richard7, Starman81 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 4890

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics