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Barkonian ATM RFT Refractor Project

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#1 Charlie Hein

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Posted 30 June 2012 - 11:36 AM

Barkonian ATM RFT Refractor Project

By Kevin Barker

#2 cheapersleeper

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Posted 30 June 2012 - 08:31 PM

Great idea!!! I would love to put my Dob building skills into a refractor.

Regards,
Brad

#3 Rayh

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Posted 01 July 2012 - 04:05 PM

This is partly my problem because I am not an ATM but this article really would have been better if there were a single labeled sketch to see what the optics are on the finished product.
Ray

#4 Kevin Barker

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Posted 03 July 2012 - 02:16 PM

Rayh
You are right I should have put a sketch of the optical config in the article. Although I have described the way I went about it. It is basically all wood. I made this scope just before rushing off for a Venus transit trip to Northern Australia.

Note in the shot below one can see the three 32 mm screws which hold the back plate with secondary assembly in place.

Kevin B

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#5 Kevin Barker

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Posted 03 July 2012 - 02:29 PM

The shot above includes screws which I used to help align the secondary. I removed them. One can also see the central 7 mm bolt and the three 6 mm bolts screwed through the ply. These are used to adjust the secondary tilt.

Below is a shot of the method I used to set objective. note ; I used sandpaper shims as well well as blocks which were screwed down firmly when i was satisfied I was reasonably central.

Although this looks crude it was quite easy after carefully screwing in place then adjusting the secondary to get a laser beam and chesire cross hair collimator to show the optics were well aligned. I have been using this scope daily and it has retained good collimation.

Kevin B

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#6 Rayh

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Posted 05 July 2012 - 09:45 PM

Thanks, Kevin! I get it now. Somehow my brain was thinking a curved secondary.
Ray

#7 Kevin Barker

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Posted 07 July 2012 - 06:56 PM

Ray
I did consider making a spider but then thought cutting a 40 mm diameter circular piece of timber and mounting to a back plate was easier to fabricate.

It worked!!!

Kevin






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