Finished earlier than expected...EQ mount specs.

[asimov]

Feel free to down-load the plans. Hope it helps somebody out.

[asimov]

Some pics to go with the article. Sorry about the quality!

[fringe_dweller]

Wow! John - effort mate!! looks clearly and well laid out :)
Kearn

[mch62]

Nice rig there .
Great to see another DIY getting the courage up and giving it a go.
You must be real proud of what you have accomplished.

What is your profession?
Just curious to see .
You would be surprised at the skill levels people have that under take such a project.
I know it's not for every one but when it come to the money crunch and you have your back to the wall , it's amazing what us amateur astronomers are capable of.

My only comment is I would have made the shafts about 40 - 50mm or a bit less for a 12" newt .
Even thick wall hollow would be fine to keep the weight down.
An EQ6 for example has 11/2"shafts and a Losmandy 11/4" and really were to light for my 16kg 12.5" f6 and the torque required was to much for the small size of the 5.6" EQ drive gears but if your happy with them so be it.

When you come to fit drives don't skimp on the diameter of the gears.
8" would be the minimum for a long Newt and really for imaging bigger will be better.
The Dec shaft could be a size smaller to save $ but the RA shaft is the one doing the most accurate work.

It's not the weight of the scope that is the problem , it's the long tube and the torque generated when slewing or stopping.
If the gears are not up to it you will have a scope that feel as though it's on jelly.

Here are a few links for over seas gears I checked out at one stage.

It is possible to get them made but this is an exercise in frustration trying to find some one with the expertise.


http://www.beaconhilltelescopes.mcmail.com/

http://www.opticcraft.com/

http://www.aeroquest-machining.com/index.html

Then comes the fun part with drive controllers.

Hope this helps with your project.

Mark

[asimov]

Hello Mark, & thanks for your kind comments. My 'profession'....I'm not officially qualified in any field, unless you want to take into account 35 years {off & on over the years} of basic engineering/design/welding etc. etc. My father was an engineer, & fundamentally with his input of knowledge and my labour, we made our first EQ mount when I was 13....So I picked up the knowledge on THIS basic EQ mount design from him, along with some new idea's that popped into me head as I was making it.

I was on a definite schedule when I constructed this last mount. In 2 weeks I had to design it, come up with the materials & build it. It's safe to assume that SOME of the materials used, were not picked by choice, but by necessity. {limited material choices where I live} In the last page of the plans I discuss what I would have liked to use instead of what I went with.

As far as driving it, I've already made a radial arm equal to a 22" {508mm} dia. gear.
Using a double curved bolt system requiring a 1 RPM motor to drive it. I've had it working, but the AC motor I was using was inducing high frequency vibration between the medium to high ranges of magnification.

Right now I'm mucking about with another drive idea using super magnets...totally isolating the drive/source physically from the telescope altogether. The results are......pending :) Thanks for the links.

Kearn.....Ta mate. :)

[ving]

woah! very nice looking job!@ :)

[atalas]

Nice work John,thanks for posting.

Louie :thumbsup:

[asimov]

I'm BUMPING this thread because some of you guy's on here think that a EQ mount to hold a big reflector is TOTALLY out of reach, construction & money wise....I'm here to tell you it doesn't have to cost 6K to get this...If you make it yourself, it's going to cost less than 1500 bucks....If you get someone to make it for ya? I dont know. This mount hold's my 80 lb OTA no sweat! Run your eye over the plans dude's....If you dont like the design....dont build it...If you do...get crackin'!

[davidpretorius]

cost for someone to make it for you? does anyone know a top bloke from say australia, maybe even south australia that could make a really fantastic excellent mount. I have included a picture of one that i found on an excellent forum site called icein something.

http://www.iceinspace.com.au/forum/attachment.php?attachmentid=2483&stc=1&thumb=1 (http://www.iceinspace.com.au/forum/attachment.php?attachmentid=2483)

This most fantastic guy really knows his stuff! If anyone knows how to contact him, I reckon we could con a few free mounts out of him for testing purposes of course.

I believe the line starts here gentlemen for guys wanting a free one to test and then goes way way back.

IN all honesty, this is great. I can see that i am going to have to try this.

That Asimov, he is always making you think!!! Just when you thought it was safe to buy a dob!

[asimov]

Yep. The dividing line start's right here Gent's! I'm not offering to make it....NO access to a lathe these days, so dont ask. Dont get me wrong...I would LOVE to knock up half a dozen of these baby's & flog em' off because I'm currently unemployed. I'm just offering....for the guy's that have the inclination, the time & the required tool's to build this mount. If I was in a position to make them, I wouldn't have dared put the plan's up on here for all to see now would I !?? And it's not like Iv'e got a patent on it or anything, lol..I'm here to help you guy's out...FREE...GRATIS.

Don't winge about not having an EQ mount big enough to swing your 8" right up to a 12.5" reflector, & therefore your committed to buying a dob..:violin::P

Because you have option's! If you dont wanna make it yourself (or can't) down-load the plans and take em' to an engineer & see what he reckon's.

Have a good evening, Gentlemen! :thumbsup:

[asimov]

DOINK! :D

I don't like the word 'bump' :P

Doing this on behalf of a relatively new forum member, not cos' I'm vain..:thumbsup:

[netwolf]

thanks asimov. wow, so much talent in this great nation of ours.
So this is the pupy you were hel bent on driving for <$100 , hats of to you.
Does it have room for a polar scope.. I mean to say is the polar axis holow.

[asimov]

The RA shaft is hollow. A polar scope would not be do-able because The DEC shaft would be directly in the way. I spent time drift aligning...good enough for me. It's not the kind of mount to be pulling apart every morning to stick in the cupboard after youv'e finished observing, It's a permanent fixture in the backyard. Set the polar alignment once, then forget it.

& thanks for the hats off re: the drive. I'm still modding it, now I'm adding a drive to the DEC axis & fast slewing to both RA & DEC & slo-mo controls.