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Subdeo

Beam splitter conundrum

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Does anyone have any ideas on how to make a DIY beamsplitter to be used in a very basic homemade binoveiwer lens? It needs to have a 45deg. angle of incidence (I think that's what it's called, right?) and a 50/50 ratio. Thanks, 

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There's a video halfway down here: https://stereoscopicmirror.com

I don't know if this material is flat enough for your purpose. I think you want something to the standard of a star diagonal. Or twice as good because the transmitted beam will have to pass through two surfaces. And after that there will be more reflections needed. You'll need a clever design.

Another option is using a beam splitter prism. You'll find some here: http://www.ebay.com/bhp/beam-splitter

Of course, everything will have to be mounted to exact tolerances.

This search may help you further: https://www.google.nl/search?q=DIY+binoviewer&newwindow=1&client=opera&hs=MEs&source=lnms&sa=X&ved=0ahUKEwjppZzwn73aAhWGGuwKHQHnCDQQ_AUICSgA&biw=1519&bih=907&dpr=1.1

Good luck. You'll need it. What you want is not all that easy!

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I think you could bond two right angled prisms to form a beam splitter cube using Canada balsam. It would depend on the accuracy you need for your purpose as to whether this would be feasible.

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I can't help with any advice on making one but I can recommend Surplus Shed (link below). I bought a beam splitter and a few other items for an interferometer that I made a few years back. They were excellent value and are really reliable; I since bought a few other items from them and have never been let down.

Surplus Shed 

 

Jim

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Thanks all, a big help.

   When (and if) I am successful, i will try to post about it. It may end up taking me till summer break, though!

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Hey, Tyler, I saw your eclipse video on youtube. 

Enjoyed that. Really nice! 

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1 hour ago, Ruud said:

Hey, Tyler, I saw your eclipse video on youtube. 

Enjoyed that. Really nice! 

Thanks, glad you enjoyed it! 

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finally, (partial) success! 

I was able to use a microscope coverslip to achieve much the same effect as a beam splitter (see the below picture). I was actually really surprised to see how well it worked on the telescope, as it actually let me see where the telescope was pointed, from both sides! Still bugs in the system, but I am working on it. Primary annoyance: Hot glue obscures the view! 

  This is obviously still in beta version, so I will replace it with a more functional, professional glass piece. This is still just proof of concept. I will try to keep all posted!

Thanks for the help!

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We used various beamsplitters and the beamsplitter cubes from Surplus Shed in the early Spectra-L200 spectrographs.

Cheap and effective.

The microscope slide gives a reasonable 90/4 beamsplitter with some residual astigmatism. I used a Vixen flip mirror housing to hold the beamsplitter, it has T thread connections on the output ports.

 

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7 hours ago, Merlin66 said:

We used various beamsplitters and the beamsplitter cubes from Surplus Shed in the early Spectra-L200 spectrographs.

Cheap and effective.

Thank God for US military and corporate surplus. :lol:

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  • Haha 1

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This morning I replaced the glass piece with a different one that was better, and less broken. I gave it a full test, and hooked up the camera to it. It worked like a dream! I could actually see through one eyepiece myself, while the camera was poised and ready on the other side. :)   The side with the camera was noticeably dimmer, but not enough to be an annoyance.

  After a few more tests, I think I will be ready to use it in the field. 

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