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17" CDK and Equatorial Mounting

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324 replies to this topic

#1 zytrahus

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Posted 02 August 2012 - 02:02 AM

Hello,
I've been working on this for a few weeks already and figured it was time to start to create some kind of work log on here.

I am building a 17" CDK f/6.8 (though I will be buying the optics i.e. mirrors and correctors) and equatorial mounting for it.

All the parts for the telescope have been made already and I have started assembly already. Though I am a little behind on the work log so I will be posting quite a few updates within the next few days!

The assembly should be finished soon, though since I have not ordered the mirrors yet (still saving up) the telescope will be waiting a few months before it sees a light. That being said, I am finishing up the design of the equatorial mounting and should be able to start machining parts shortly. The mount will be tested before the telescope as I have already ordered the worms/gears/motors. This should keep me busy till at least I have the resources for the optics!

I will be keeping my blog updated as I progress.

Here's the first blog entry: http://cooledpix.com...7-introduction/

and a couple pictures of the CAD work.

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Feel free to ask questions about the design. I will populate my entries with as much information as I can.

#2 kfrederick

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Posted 02 August 2012 - 05:52 AM

Nice CAD work!! What is the mounting look like?

#3 polaraligned

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Posted 02 August 2012 - 06:11 AM

Looks very good. Are the optics from the same source that Planewave uses? I only ask because 17" is not a common size.

Also, how are you able to determine that the center ring where the truss attaches will be stiff enough? I see it is cored out there. Did you do any FEA on it?

I will be following your build with interest. Thanks for posting.

#4 zytrahus

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Posted 02 August 2012 - 11:28 AM

I will post the CAD work for the mounting when I am finished. It slightly differs from a traditional GEM. It's all I say for now :)


I am not sure where Planewave is getting the optics. But yes it is the same diameter and f ratio.

Yes, the middle cell openings were checked with a static analysis of this middle cell.

#5 The bear

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Posted 02 August 2012 - 03:07 PM

this one is so cool i love it i sent you an pm zytrahus
doc

#6 allardster

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Posted 02 August 2012 - 07:27 PM

Interesting project, great CAD work.

#7 Dave O

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Posted 02 August 2012 - 10:32 PM

Looks like a nice compact design. 17" f/6.8 with two corrector lenses ... do you have a prescription for this design? I'd like to see its 'performance' ... ;)

#8 zytrahus

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Posted 03 August 2012 - 01:20 AM

Thanks guys.
I'll post some optical data soon.

Adding a picture of the parts (they're not all in there) after they came back from anodizing.

The tube assembly in the middle is the corrector/baffle assembly.

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#9 TopherTheME

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Posted 03 August 2012 - 01:31 PM

Very nice. Where are you getting your parts anodized?

#10 zytrahus

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Posted 03 August 2012 - 01:36 PM

A small local shop that goes different kind of plating jobs.

#11 zytrahus

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Posted 03 August 2012 - 10:37 PM

Quick update for the rear cell assembly:
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blog entry: http://cooledpix.com...dk17-rear-cell/

#12 polaraligned

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Posted 04 August 2012 - 08:38 AM

Primary is going to be glued in place?

#13 zytrahus

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Posted 04 August 2012 - 01:37 PM

Nope there is a 18-point floating mirror cell in between the mirror and back plate. More on this very soon :D

#14 polaraligned

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Posted 04 August 2012 - 05:30 PM

Only reason I ask is because Planewave glues theirs. Seem it would simplify things. But they are using a conical primary, you obviously are not.

#15 zytrahus

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Posted 04 August 2012 - 08:08 PM

the mirror will be glued on the 18 point mirror cell, but I wanted to have some freedom adjusting the primary although collimation should not be too much of a problem. Time will tell =)

#16 zytrahus

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Posted 05 August 2012 - 02:29 AM

A couple more pics for the Mid Cell assembly.

http://cooledpix.com...cdk17-mid-cell/

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#17 johnC

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Posted 05 August 2012 - 04:50 AM

A work of art.
Just stunning.

#18 TopherTheME

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Posted 05 August 2012 - 12:26 PM

Whats the approximate weight of this thing going to be?

#19 zytrahus

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Posted 05 August 2012 - 12:51 PM

just about 37 Kg

#20 Dennis Sakva

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Posted 05 August 2012 - 01:21 PM

Stephen and how thick is the backplate?

#21 zytrahus

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Posted 05 August 2012 - 08:32 PM

1/2" - I'll post some pics on the mirror cell itself soon

#22 zytrahus

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Posted 07 August 2012 - 03:16 AM

quick update for the primary mirror cell (18 floating points)

blog + info + pics: http://cooledpix.com...ry-mirror-cell/

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#23 zytrahus

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Posted 07 August 2012 - 08:52 PM

Another quick update: assembly of the front cell/spider.

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http://cooledpix.com...k17-front-cell/

#24 rogercelliott

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Posted 07 August 2012 - 10:17 PM

Wow... awesome. I so miss having access to CNC machine tools!
Cheers
Roger

#25 zytrahus

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Posted 08 August 2012 - 09:36 PM

Here's the vane preloading mechanism for the spider.

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