DIY homemade telescope mount project

[Tom How]

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.

As programming tasks go, creating an ASCOM driver is pretty trivial. The ASCOM chaps have it made it foolproof with lots of lovely templates and genuinely useful documentation.

It would be fairly accurate to say something like 95% of the programming time was spent on the C++ for the Arduino and the other 5% putting stuff into the .net ASCOM driver

Particularly as my ASCOM driver doesn't do anything except shuffle commands. If an application wants to know the local sidereal time, it asks the ASCOM Driver telescope.Sdierealtime(). My ASCOM driver sends a serial command to the Arduino ( like ":GS#" ) and waits. Arduino consults a separate real time clock hardware module (no RTC on this arduino) for the correct local time. Arduino then performs the calculation to get LST and sends it back up the serial port. My ASCOM Driver reads this and sends it back to the application that originated the request.

The algorithm to convert from local time to LST is probably the most used function in the Arduino code. It is called a heck of a lot when doing a GOTO

[Gina]

Thanks

[angusb1]

Hi Tom,

I have looked into making a mount because I like to know how these things work and I like to make things for my hobbies too, and came across your article on making worm and wheel sets. Nice to see you on the forum and I take my hat off to you for not just building all this stuff yourself but for taking the time to show the rest of us how you did it.

What's your next astro project?

[fwm891]

Have to agree with Tom - a lathe is a much 'handier' piece of kit. You can also do some quite complex milling jobs on a lathe with some quite simple add-ons...

[JamesF]

I'd love to have a lathe. I was in possession of an ancient Boxford machine at one point, but my dad decided he wanted it back. I'm not sure it would have been ideal anyhow because IIRC it still had an imperial leadscrew.

The real problem, like quite a few things these days, is finding someone who can teach you to use it properly when you just want to do so as a hobby...

James

[JamesF]

Oh, all the controls were marked up in thousandths of an inch and so on, too. I can't cope with that

James

[fwm891]

I'd love to have a lathe. I was in possession of an ancient Boxford machine at one point, but my dad decided he wanted it back. I'm not sure it would have been ideal anyhow because IIRC it still had an imperial leadscrew.

The real problem, like quite a few things these days, is finding someone who can teach you to use it properly when you just want to do so as a hobby...

James

James, Its quite easy to get hold of new or s/hand gears to convert the 'imperial' leadscrew to metric units. My old Myford speed 10 has an imperial leadscrew but its quite easy to turn filter threads of 0.5 /0.75 pitch etc... TBO if all your making is filter adapters using one or two thread rotations you can get away with a very close imperial unit without damaging the filter...

As for learning to use a lathe there are a number of retailers (e.g. Axminster Tools) that offer short courses - try the local tech College or a local Model engineering club (like this forum) members usually want to help people willing to learn...

[skybadger]

Hi Tom

nice machine.

Am I correct in assuming that the worm wheel cover is a cut-down bake tine or is it something you made up yourself ?

Cheers

Mike

[JamesF]

I'll see if I can find a local model engineering club. I've given up hope with the local tech college. I applied to do an evening course there a few years back on "proper" woodworking in an attempt to better my bodging skills, but it was cancelled due to lack of interest. Same with welding. Looking at the most recent brochure, if you want to do "beauty therapy", "computers for thickies" or "advanced macrame" you're well catered for. Proper engineering type stuff doesn't seem to be an option any more though

James

[fwm891]

James, If all else fails look at these books:

http://www.amazon.co.uk/The-Amateurs-Lathe-Lawrence-Sparey/dp/0852422881/ref=sr_1_1?s=books&ie=UTF8&qid=1340987007&sr=1-1 and:

http://www.amazon.co.uk/Model-Engineering-A-Foundation-Course/dp/1854861522/ref=sr_1_1?s=books&ie=UTF8&qid=1340987077&sr=1-1

The Sparey book is a basic bible on small lathe work, the Model Engineering-A foundation Course will give a broader outline of many engineering facets...

[JamesF]

Thanks Francis. I shall look into those.

James

[Tom How]

Hi Tom

nice machine.

Am I correct in assuming that the worm wheel cover is a cut-down bake tine or is it something you made up yourself ?

Cheers

Mike

Completely correct

It is a cake tin that cost a couple of quid from the supermarket. I don't see much point doing tedious sheet metal fab when the perfect part is on the shelf at the local shops. The paint was my addition.

[Tom How]

Hi Tom,

I have looked into making a mount because I like to know how these things work and I like to make things for my hobbies too, and came across your article on making worm and wheel sets. Nice to see you on the forum and I take my hat off to you for not just building all this stuff yourself but for taking the time to show the rest of us how you did it.

What's your next astro project?

Thanks I have no idea what's next. Got to get this working properly first before distracting myself too much.

[Tom How]

I'd love to have a lathe. I was in possession of an ancient Boxford machine at one point, but my dad decided he wanted it back. I'm not sure it would have been ideal anyhow because IIRC it still had an imperial leadscrew.

The real problem, like quite a few things these days, is finding someone who can teach you to use it properly when you just want to do so as a hobby...

James

I don't think anybody taught me.. but i don't make any claims about doing stuff "properly". For me, a huge amount of knowledge can be found on websites and youtube videos. A lot of time for trial and error helps.

And nothing wrong with an imperial machine. You only HAVE to use a metric machine or conversion if you're making the thingy that screws into a purchased device... and to be honest, you do that a lot less than you might think. Buying an extension tube is usually the best course of action anyway. Making an extension tube is difficult - tough to get both threads concentric.

That entire mount could be made quite happily on an imperial machine: You'd just use 16tpi for the worm wheels instead of 1.5mm pitch.

[Tom How]

Have to agree with Tom - a lathe is a much 'handier' piece of kit. You can also do some quite complex milling jobs on a lathe with some quite simple add-ons...

It is always worth reminding people that you can turn a cube on a lathe - they aren't limited to round stuff. And yes, whilst we're at it, you can drill a square hole as well.

[skybadger]

It is always worth reminding people that you can turn a cube on a lathe - they aren't limited to round stuff. And yes, whilst we're at it, you can drill a square hole as well.

I can see how to turn a cube - put the cube on the faceplate and turn a side at a time. Other than broaching I can;t see how to cut a square hole - or is that the triangle cutter thingy ?

Mike

[JamesF]

I'd guess it's a "triangular" cutter. I think that's the way it's done in wood for cutting mortices using a drill.

James

[Stardust]

I'm very impressed by this project, excellent work

[Tom How]

Cleared up enough over the weekend to spend an hour or so messing with the DIY telescope mount.

Very difficult times: Just as it finally gets dark your brain wants to go to bed. The last thing you want to be doing is tough thinking.

Managed to find a target ok, and proceeded to grab a couple of 15 minute frames which came out ok.

Problems mainly with the tracking. For reasons beyond me it seems to suddenly loose about 5 or 10 arc seconds in position every couple of minutes, but there doesn't seem to be a pattern. Could of course be the guiding software itself, but normally that is pretty reliable.

Dec guiding is also far from right, but i didn't dwell on that too much.

http://astro.neutral.org/images/20120630-6888-2.jpg

[Tom How]

I'd guess it's a "triangular" cutter. I think that's the way it's done in wood for cutting mortices using a drill.

James

yes, you need a triangular cutter and a weird movable chuck widget as well. Can't say I've ever needed a square hole, but the point is a lathe is pretty flexible if you've got some imagination.

[fwm891]

Well I guess someone will have found out how to 'drill/mill' a square hole...: http://cuttingtoolschicago.com/metalcuttingtools/drill-square-holes/

[JamesF]

I can't help but have respect for the person who invented the first one of those. It's so wonderfully implausible

James

[Tom How]

I have an update!

Earlier this year I finally got fed up of running the homemade telescope mount with a set of old Meade DS motors and an ancient Autostar controller.

The system was too slow, a bit flakey, I can't maintain it, and I can't add new functions etc.

So in Feb this year I started a project to replace the telescope control system with a complete homebrew system built around an Arduino microcontroller.

• Maxon coreless DC servo motors with encoders
  
• Arduino Mega 1280
  
• Home / PEC sensors
  
• Dedicated ASCOM Driver
  

Happy to say it is all up and running now!

Page about the Arduino ASCOM telescope control system

[Gina]

Very interesting and great work This is something I would like to do one day. Maybe make a small low powered mount to run my widefield system. I have an NEQ6 Pro as my main mount.

[Mondriaan]

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,

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