DIY homemade telescope mount project

[Cornelius Varley]

Hello, great project you are doing, i have already a lot of new information about the equatorial mounting through you, one question:

You have on your site a link to

Construction Notes For a German Equatorial Astronomical Telescope Mount

http://www.astronomiainumbria.org/advanced_internet_files/meccanica/easyweb.easynet.co.uk/_chrish/eqnotes.htm

there should be 13 plans for building the mount but there are only 3 zip files, do you have contact with the author of that site?

Secondly, maybe that this is the wrong place to talk about the matter, i am looking for a good plan (design ) of a professional foucault tester ( the most plans i find are not complete or are build of wood).

Thank You,

Quote from Red Dwarf (the BBC tv series)

" No look, I'm you from the future. I've come to warn you that in 3 million years you'll be dead! "

- Rimmer, Stasis Leak

The site was last updated Dec 1999. It could be that the project was never completed and no drawings are available. 

[ChrisLX200]

The project was completed but apologies for not completing the drawings - it took longer for the drawings than it did for the machining! (and I was no expert at AutoCAD anyway). I had a break shortly after for health reasons.

This was the completed mount at work carrying a 12" Newt, and also as a camera mount. 

ChrisH

[Mondriaan]

No apologies needed, thanks for your information.

Judging by the pollution content of the atmosphere, I believe we have arrived at the late twentieth century.
--Spock in 'The Voyage Home'

[Cornelius Varley]

The project was completed but apologies for not completing the drawings - it took longer for the drawings than it did for the machining! (and I was no expert at AutoCAD anyway). I had a break shortly after for health reasons.

 

 

 

ChrisH

That would account for it.

[Mondriaan]

Good morning, i have a question you are talking in the links about 2 1206 ETN9SKF Self Aligning Bearing, can you hint me where you placed these self aligning bearings (declination shaft or RA shaft or each shaft one on the top or bottom) ?

Richie: We're really the guuuys aren't we?

From: Bottom

[ChrisLX200]

Good morning, i have a question you are talking in the links about 2 1206 ETN9SKF Self Aligning Bearing, can you hint me where you placed these self aligning bearings (declination shaft or RA shaft or each shaft one on the top or bottom) ?

Richie: We're really the guuuys aren't we?

From: Bottom

It's perhaps more important for the RA axis, but fitting to both RA and DEC is a good plan. You just need one per axis (either top or bottom, TBH I don't recall which end I placed mine). My problem was that I did not have access to a jig borer which would have guaranteed the seats for the bearings were perfectly aligned to very tight tollerance. The RA axis assembly consists of two bearing housings bolted onto a plate so to ensure the two bearings worked well together some allowance for self alignment is required. Ordinarilly this entire part would be a large casting with the two seats bored together on a jig borer. I suppose if you insisted on using ordinary bearings then you could machine the bearing recesses a few thou oversize and use a bearing retaining compound to fill the gap, the two bearings being held in position by the RA shaft while this was done. Not pretty, but it might work well enough.

ChrisH

[Mondriaan]

Thanks, very clear. I was a lot of years ago working on a small telescope, i am now orientating again and searching for the good info, i found here very good information, i was in the past (a lot of years ago) in a dutch assocation for weather and astronomy specially for the practically side (making mirrors and moutings) but this practically workshops are not there anymore so im looking on the internet, so very thanks.

[Mondriaan]

I am now searching on the site of Maxon Motor and i would ask you if you chose for a ready design or configured itself, the site gives the possibility to do itself, there are 5 motor models DCX 10L, 10S, 22L, 22S and the 35L, i think the main question is how much torque i need.

Further i get a set of choices,

Shaft: Lenght, flat, cross-bore,keyway, diameter, mounting flange.

Flange: Amount and position of the thread holes, size of the thread holes.         

             central thread on small diameters.

Number of stages in the gearhead: Reduction in 1 to 5 stages.

Bearings: Ball or sleeve bearings.

Windings: Various nominal voltages.

Commutation: Precious metal or graphite brushes, with or without CCL, with or             

                      without electromagnetic interference suppression.

Contacts: Terminals or cables, cable lenght, with or without plug, choose          

                orientation of connection in reference to gearhead or flange.

Sensor: EASY or QUAD.

Cable Design

Did you choose:
1.    High Performance
2.    Dynamic
3.    Low Noise
4.    Fast Processing

I hope I'm not annoying, but the choices are not the cheapest and I would not like to have motors that I can not use.

[ChrisLX200]

I am now searching on the site of Maxon Motor and i would ask you if you chose for a ready design or configured itself, the site gives the possibility to do itself, there are 5 motor models DCX 10L, 10S, 22L, 22S and the 35L, i think the main question is how much torque i need.

Further i get a set of choices,

Shaft: Lenght, flat, cross-bore,keyway, diameter, mounting flange.

Flange: Amount and position of the thread holes, size of the thread holes.         

             central thread on small diameters.

Number of stages in the gearhead: Reduction in 1 to 5 stages.

Bearings: Ball or sleeve bearings.

Windings: Various nominal voltages.

Commutation: Precious metal or graphite brushes, with or without CCL, with or             

                      without electromagnetic interference suppression.

Contacts: Terminals or cables, cable lenght, with or without plug, choose          

                orientation of connection in reference to gearhead or flange.

Sensor: EASY or QUAD.

Cable Design

Did you choose:

1.    High Performance

2.    Dynamic

3.    Low Noise

4.    Fast Processing

I hope I'm not annoying, but the choices are not the cheapest and I would not like to have motors that I can not use.

I can only be of limited help here. I recycled the motors and driver PCBs from a scrap medical infusion machine, the motors being geared DC Servo while the elctronics allowed precise rate control (as can be imagined for a device like a medical infusion pump!). I needed to add an intermediate gear for the worm drive to bring the rpm and torque of the motor down into range required. There were complete (2x drives plus controler) commercial systems that could have been fitted but they were too expensive for me at the time.

ChrisH

[Mondriaan]

Thanks ChrisH, i will look into it.

[Mondriaan]

I made contact with Maxon Motors, this is the response I got from them (translated from dutch).

Mail 1:
Can you also specify the required torque and speed. Otherwise, indicate what is in it or indicate what is to be driven.

Mail 2:
Could you send me product numbers of the motors and controllers. The numbers consist of 6 digits. If this is difficult then you may send us pictures where the number of items to be sent?

So far the communication with Maxon.

Maybe if i would find the specs of the meade motor and point them to what needs to be better (quicker, sufficient powered and reliable) they could use this information (but i dont know if they are allowed to use information from Meade), I would be happy to share the information and experience I get from Maxon Motors to put this on Stargazers Lounge.
------------------------
What I have found so far about torque, there are three main engines, the DCX 10L (1.78 mNm), DCX 22L (23.92 mNm) and DCX 35L (102.4 mNm), I searched the internet for a good calculation formula to convert kilo across this mNm (I believe I can put on this site no direct links so I try to describe it), the formula there

200 gram-force centimeter 19.6133 mNm

So to move a telescope of 200 grams of an cm I need the DCX 22L.
to move a telescope of a kilo I need the DCX 35L

What do I calculate wrong, or is this taken care by the counterweights?

[Mondriaan]

Gearhead
http://www.maxonmotor.com/medias/CMS_Downloads/DIVERSES/GPX_22_en.pdf

Sensor ENC 30 HEDL
http://www.maxonmotor.com/medias/sys_master/8804422483998/SENSOREN-Das-wichtigste-ueber-SENSOREN-11-DE-EN-ES-030-031.pdf?attachment=true

[Mondriaan]

The Maxon site has its own configurator, if my explanation not works (im only an amateur) maybe that this then works.

http://dcx.maxonmotor.com/maxon-dcx/eng/configurator.jsp#.UynfOqK-2So

[Mondriaan]

Oke i understand now that i first have to assemble the telescope to find the information to purchase the right motors,

Thank you

[Mondriaan]

Hello, i have made contact with a firm that makes wormwheelsets, i found a site C3 Mini-Lathe Metalworking Beginners (i believe that it is your site) you give a formula to calculate the diameter of the wormwheel [ (360+2) * pitch ] / PI
i would like to ask you that if i choose for a pitch of 2 if it is right that the diameter will be 230.46, which depth of the cut would you prefer?