2.12" viewport not big enough

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David Kunkle
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2.12" viewport not big enough

Post by David Kunkle »

I already have a 2.12" CF viewport. Finalizing things before everything gets welded together in about a week. When putting the viewport in position and looking thru it into the chamber, I realized I can only see about 8 inches in diameter of the opposite chamber wall. The chamber is 20" in diameter. I would like to have far more than that within the camera's view. Cutting down the nipple would help only marginally to get a wider view. I'm thinking I need to go up to a 2.75" or even 3.38" CF viewport to get a decent field of view.

I know only a small viewport is usually needed for viewing and to keep X-rays in the chamber. But with my 20" chamber, I don't see that I have a choice. Am I missing something? Thanks for any advice.
If your experiment needs statistics, you ought to have done a better experiment.

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Richard Hull
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Re: 2.12" viewport not big enough

Post by Richard Hull »

Question. What to you expect to see in other parts of the chamber when all the acion is in and around the inner grid?

A modern, small, board camra with tiny lens can be jammed against the glass and give a very wide angle view. I assume you will wisely never view directly with your eyes while fusion is going on. I have a 3/4" view port glass in a 2.75" view port and use a small board video camera and do just fine. 1" diameter glass should great.

A larger view port is fine, of course. Your choice.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
David Kunkle
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Re: 2.12" viewport not big enough

Post by David Kunkle »

Down the road among other things, several W filaments that I would like to monitor visually. Now that I think about it, will the glow from filaments wash out the video?

Just found a 1/3" Sony board camera on ebay that I think I will grab. Also have a monitor laying around, so I should be near complete there.

Will not be viewing with my eyes even if fusion isn't going on.

At least wanted to check with the forum if there was some other way to get a larger field of view without going to a larger port.

Thanks for any other input, Richard.
If your experiment needs statistics, you ought to have done a better experiment.

Ernest Rutherford
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Richard Hull
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Re: 2.12" viewport not big enough

Post by Richard Hull »

You will like the little sony board cameras, they have a very wide angle lens without going to a fish-eye view. They will do a sharp focus ,(manually), from about 1/2" to infinity.

Remember, with the lens pressed against the glass view port, a 3/4" viewport will yield the same camera image as an 8" diameter glass view port.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
David Kunkle
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Joined: Thu Apr 17, 2014 12:43 pm
Real name: David Kunkle

Re: 2.12" viewport not big enough

Post by David Kunkle »

Looks like the minimum illumination of the Sony is about 10x's better than the other ones I looked at also.

With your last post, I still feel like I'm missing something. The viewport's glass is just under 1" diameter and mounted in a 2.12" CF. This in turn was going to be mounted to a 2.12" CF nipple.
I have a great view inside the chamber if I put my eye up to the viewport only. When I attach the viewport to its nipple, the tube of the nipple is what greatly cuts down the field of view. Is the viewport supposed to be attached more directly to the chamber without a nipple?
If your experiment needs statistics, you ought to have done a better experiment.

Ernest Rutherford
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Richard Hull
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Re: 2.12" viewport not big enough

Post by Richard Hull »

That's your problem, never put a viewport on a nipple. I welded my Conflat fitting directly to the sphere and then mounted the windowed CF fitting on to that. Nice viewing angle.

How did I do it?

I took a threaded, non rotatable 2.75 CF and machined away the back side to create a weldment lip of about 0.2-inch depth and bored the chamber to mate with this lip and just welded it on. All pro welds are made on the inside of a chamber only.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
David Kunkle
Posts: 284
Joined: Thu Apr 17, 2014 12:43 pm
Real name: David Kunkle

Re: 2.12" viewport not big enough

Post by David Kunkle »

I wound up talking to the engineer at LDS, and exactly what you stated is one solution he gave me. They can also make the conflat you described. If I go that route, I'd probably have them do it. I have no machining equipment or experience.

Thanks for the help.
If your experiment needs statistics, you ought to have done a better experiment.

Ernest Rutherford
Dan Tibbets
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Re: 2.12" viewport not big enough

Post by Dan Tibbets »

Another option may to be to place a lens on the viewport. A divergent lens may greatly increase the field of view- at least visually. Often an appropriate lens can be obtained by dissecting old slide projector lens assemblies or other lens assemblies.

Dan Tibbets
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