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ArcticMyst Security by Avery

Beam Expander query

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I own a fairly powerful telescope "Nexstar SLT5" or somthing or other..
The question is if I was to fire a laser down the eyepiece into the telescope would it expand or would I need to do it the other way around.. I imagine that would make a tighteter beam..?

Warm reguards,
Marcus
 





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I think using a small MONOCULAR would be a lot smaller & easier to wield. It would only add about 5" length to your laser...............rob
 
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Yes, it will work. This is what an expander does. Expanding the beam to reduce the divergence. If your telescope is a 200x the beam will have 200x less divergence and will be 200x bigger in terms of area.

What the guy in the video is doing is nothing else than first expanding it and then contracting it again. There's no other way to focus a laser at 300 feet.

Btw, I think the controls on the telescope that allow you to focus the image properly in your retina is the trick on the video, I can't think of any other cheap/easy way to focus it at exactly 300.00 feet ;)

Yours,
Albert
 
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How far away would you be able to focus a laser through a 10X monocular that has a focus adjustment. Also, does it make a difference how close the 'scope, monocular, etc, is to the aperture of the laser ? Thanks, rob
 
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I'm basing my answers on basic optic physic laws, so take my answers as "in theory" ;)

How far away would you be able to focus a laser through a 10X monocular that has a focus adjustment

In theory as far as you want. I guess the problem is that with low magnifying ratios low distance adjustments affect dramatically the results making it impossible to use cheap optics (like a 10x monocular) to focus at high distances.

Also, does it make a difference how close the 'scope, monocular, etc, is to the aperture of the laser

Yes, because due to the divergence the laser beam will be different at every single different distance. This is translated in a different "maximum focused" distance, but in theory you can focus every laser at every distance with every optics.

Of course, you have to consider that every optic the laser pass trough is translated in a "beam quality" loose, making the work harder.

Yours,
Albert
 
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Well the optics in the monocular that I have aren't cheap. This was a fairly expensive unit & has AR coated optics in it. I'll have to give it a whirl & report back with some results............rob
Thanks for answering my ?'s
 
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Last time I used my telescope for burning things I managed to destroy 2 eyepieces when I decided to stack a bunch of them one after another in a line at the other end of a telescope for a ray that was hot enough to melt the plastic and metal oh dear.
 
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One of the hazards of using hi-powered lasers around black or dark colored plastics & not being careful enough. I hope they weren't expensive pcs. that got trashed. rob
 




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