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DIY homemade telescope mount project


Tom How

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Amazing piece of work, your use of worm gears and all the fabrication complexities got me thinking would it be easier to make a friction drive?
I tried friction drive for turning security cameras but it didn't work! Too difficult to get the pressure right.
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Very nice bit of work :)

I'd love to see things like period error graphs and flexure measurements etc -- sounds like I'm about as geeky as you when it comes to these things :icon_eek:

Once I have it all tuned up I will do some graphs :rolleyes:

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Some clear skies last night before the rain. I'd made some adjustments to the DEC drive (actually had some loose bolts :) ) during the week.

Couple of 300s frames on M13. I had the Ha filter in, so rather noisy! Just calibrated, stacked and stretched a bit.

Still a bit of drag in DEC (DEC is now more or less Up/Down) but improved.

post-20774-133877617612_thumb.jpg

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LEaving the Ha filter in, moved around the sky to the elephants trunk after m13. Single 1200s frame, calibrated and stretched. Nothing else done to it.

Stars quite soft (i think my focusing is up the spout) and a tiny bit of dec egging on the stars.

More work required methinks.

If anybody else has some useful conclusions to draw from this data I am all ears!!

post-20774-13387761763_thumb.jpg

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Because of numerous questions I've made a basic parts list with URLs etc.

These are today's prices with today's vat.

I've attached it as an HTML file - hope it works. If anybody has a better suggestion let me know.

...hmmm, no it does not work

here is a direct link

http://astro.neutral.org/mount-costs2.htm

This is simply done by saving the spreadsheet as an html file

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Right, got there in the end.

When I do DIY projects, I'm usually loathe to spend money unless I feel it is important. The money spent above is therefore money well spent.

There are many alternative ways of solving the various problems, some of which are cheaper, and some much more expensive, but this is the route I took.

Original mount page

http://astro.neutral.org/homemade-diy-gem-telescope-mount.shtml

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  • 1 year later...

Happy Solstice all.

Some of you may remember me installing the homemade telescope mount in my observatory last summer. I am pleased to say it survived the imaging season!

The weather over the last 12 months hasn’t been the best, but I’ve managed to turn out a few images with the DIY mount and have a lot of fun in the process.

Unfortunately the DIY bug doesn’t sleep for long. I strongly disliked the fact I was using a second-hand set of Meade DS motors and an Autostar controller to drive the mount.

The motivations

  • Pitifully underpowered
  • Very slow slew (< 0.5 deg/s)
  • Poorly constructed feeble plastic fittings
  • All my Autostar controllers are almost worn out
  • Impossible to do any maintenance.
  • Impossible to add new features
  • All that effort on the hardware of the mount deserves a DIY drive solution.

So around about 4 months ago I decided to start a project to install my own choice of motors and make my own controller.

As you might imagine this is significantly easier said than done.

After 4 months of blundering about and ascending a sequence of increasing sharp and pointy learning curves I’ve finally got something that sort of works.

The homemade worm wheel on each axis is now driven by a Maxon DC motor + gearbox + encoder instead of the Meade DS motor/gearbox kits.

I’ve built and programmed a controller from scratch based around the well known Arduino microcontroller development boards. The Arduino is now essentially doing the job the Autostar was doing. My own ASCOM telescope driver runs on the PC allowing me to connect all the usual astro-apps (e.g. Maxim, Skymap, PHD) to the mount, just like I did before. This ASCOM driver talks to the Arduino via a USB serial port – but the ASCOM Driver is pretty much a comms hub... all the brains is programmed into the Arduino.

All the Meade motor parts and the Autostar controllers are now relegated to the spare parts bin.

Here is a short video the other day when I finally got the second motor on the system. Lots of refining and wiring and stuff to sort out, but works in principle

Crank up the volume as the mic on my iphone is very poor.

http://youtu.be/y4gC4GqYHy4

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Oh yes, very inspiring :) I'd have loved to have made my own mount but I don't have the machining facilities. I also think it would probably be "a project too far" for me now - my mental and physical abilities are not what they were. I like to think I could tackle virtually anything if I put my mind to it but I'm afraid "anno domini" is taking it's toll :(

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I have a 16 speed 10" swing lathe, made by a Company called Acorn, it needs a cog on the screw making shaft, sheared a couple of teeth off some time back, but if people are thinking of engineering bits and bobs, a Vertical/Horizontal Milling machine would be a better bet i think you could do a lot more jobs than a Lathe, but there are horses for course's so both would be nice....

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I have a 16 speed 10" swing lathe, made by a Company called Acorn, it needs a cog on the screw making shaft, sheared a couple of teeth off some time back, but if people are thinking of engineering bits and bobs, a Vertical/Horizontal Milling machine would be a better bet i think you could do a lot more jobs than a Lathe, but there are horses for course's so both would be nice....

Oh yes indeed!! :)
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I have a 16 speed 10" swing lathe, made by a Company called Acorn, it needs a cog on the screw making shaft, sheared a couple of teeth off some time back, but if people are thinking of engineering bits and bobs, a Vertical/Horizontal Milling machine would be a better bet i think you could do a lot more jobs than a Lathe, but there are horses for course's so both would be nice....

That's a tricky one... most of the time i tell people to start with a lathe... especially in astronomy where there is a need for a lot of round threaded things.

I normally only use the mill if I can't find a way of doing it on the lathe, not the other way around. But that's probably cos my lathe better made than my mill... if I had a superb mill it would be reversed no doubt.

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Interesting to see what the Ardunio is capable of as well; I've just started playing with one, great fun.

There is a lot of support out there for Arduino which make it a good platform to build a tool chain around.

You don't need a lot of power to get a lot of work done. Of the 128k of memory, I'm using about 30k for the entire program.

The 16Mhz clock might be 200 times slower than my desktop PC, but it is fast enough to do the jobs I want.

The trick is making sure the program keeps up with all the tasks without any falling behind - it can only do one thing at once. e.g. a serial request for the current RA must be serviced in a timely manner, even whilst it is in the middle of a slew - and it needs to watch that slew carefully so it stops in time!

There is no multithreading support in Arduino.

It is enlightening to see how quickly computers go once you get rid of the overhead of an operating system and just have a few dedicated lines of C++.

I'm certainly not using it to full capacity. I suspect the thing could run multiple telescopes at once.

Soon we expect the 80Mhz 32 bit version of arduino which will have even more power, should you need it. That really could control multiple scopes at once - at least until you ran out of interface pins.

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Interesting - I've yet to take a look at the Arduino - I can see that it could be useful, particularly as several people have it controlled byASCOM.

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