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Binocular collimator

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#1 btschumy

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Posted 29 July 2004 - 09:54 PM

Does anyone know if it is possible to build/buy a binocular collimator for something less than $100. I know you can "eyeball" collimation by pulling back from the eyepieces and gazing through them. But I want something a bit more precise like you do for collimating a Newt.

Bill Cook, I'm sure you have some thoughts on this. I'd also like to hear other opinions as well.

#2 BillC

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Posted 30 July 2004 - 12:44 AM

Does anyone know if it is possible to build/buy a binocular collimator for something less than $100.


The Fujinon Collimator (UBMM) costs $8,000 or more. If you can find one, a Navy MK5 with accessories costs about $3,000. I believe that the last of those were made in 1943. I still prefer to use mine for a good many jobs.

The MK5 is two large pieces of soda lime glass, convex-plano nose to back with a focal length of about f/5.

The collimator, which is no more than a large, low quality telescope . . . backwards is not the problem. Making the RIGID but adjustable test stand and auxiliary telescope, with its rhomboid prism arangement, will be the problem.

I am giving a lecture in a couple of days that I have not had tome to prepare for so I can't go into much now. But, just get an old C-11 or 14 and put a reticle at the focus and a bright lanp behind it and you will have a good stand.

The trick is NOT in aligning one telescope with the other. Trick #1 is in knowing which side to leave alone.

Trick #2 is in collimating one telescope to the axle at all positions in its swing. Once that is done, collimating the "Stationary" barrel to the "swinging" barrel will be--in most cases--a piece of cake. And by virtue of the swinging barrel already being aligned with the axle, the stationary barrel becomes aligned to it automatically.

Perhaps, more later.

Cheers,

Bill Cook

#3 Guest_**DONOTDELETE**_*

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Posted 30 July 2004 - 07:18 AM

It is Trick #1 that bothers me. For instance, at the Oberwerk support site it'll basically read that if the right image is higher than the left image, then adjust the left prism. Why not the right? Can't I equally adjust the right prism to lower right image so that it matches the left image? It seems a bit arbitary to me -- which prism to leave alone.

#4 btschumy

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Posted 30 July 2004 - 09:22 AM

The Fujinon Collimator (UBMM) costs $8,000 or more. If you can find one, a Navy MK5 with accessories costs about $3,000. I believe that the last of those were made in 1943. I still prefer to use mine for a good many jobs.

The MK5 is two large pieces of soda lime glass, convex-plano nose to back with a focal length of about f/5.

The collimator, which is no more than a large, low quality telescope . . . backwards is not the problem. Making the RIGID but adjustable test stand and auxiliary telescope, with its rhomboid prism arangement, will be the problem.

Bill Cook


So are there any plans on the net or in a book for constructing a collimator? Again, I don't care so much that it's accurate enough to get to within +/- 2 arcmin. I just want something to do a better job than eyeballing it.

With all the inexpensive Chinese binoculars out there that lose collimation so easily, I'd think there'd be a reasonable demand for something that make this job easier.

#5 btschumy

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Posted 30 July 2004 - 10:35 AM

So are there any plans on the net or in a book for constructing a collimator? Again, I don't care so much that it's accurate enough to get to within +/- 2 arcmin. I just want something to do a better job than eyeballing it.


I did find the following on a ATM list:

"Re binocular collimation

> It is quite possible, but it is time consuming and a bit
> tedious, as I have learned doing a few pair myself.
> It sure helps if you have a binocular collimator,
> but those pieces of equipment are quite expensive.

If you have a telescope ~8" or bigger, you already have a binocular collimator of sorts. Just put the binos in front of the scope, facing the scope. Mask off the scope so it sees only the binocs. The eyepieces should face a bright daylit target like the top of a power pole. Look thru the main scope & you'll see an image of the outside scene. If the binocs are not collimated you'll see a double image. To collimate you have to shift one or more of the prisms around until the images are merged in x, y, and roll. Tedious but not expensive (although I wouldn't build an 8" scope just for this purpose.



#6 lighttrap

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Posted 30 July 2004 - 10:50 AM

While it's no where near the level of accuracy that Bill Cook is talking about with those high zuit collimators, the book "Choosing, Using and Repairing Binoculars" by J.W.Seyfried contains a section on making a homemade binocular collimator out of parts available from a hardware store and from Surplus Shed.

Since that book is currently so hard to find, I'll look through my copy this weekend and try to post a rudimentary synopsis.

#7 Guest_**DONOTDELETE**_*

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Posted 30 July 2004 - 11:26 AM

Check out "Collimators & Collimation" booklet from Edmund Scientific. There is a very nice section on binocular collimation aimed at a home hobbyist. It looks like you can build a collimator for less than $100.

Also check out "Amateur Telescope Making" Book 3. There is a section writtten by Hanna called "The overhaul and adjustment of Binoculars"

Mike

#8 BillC

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Posted 30 July 2004 - 11:28 AM

Why not the right? Can't I equally adjust the right prism to lower right image so that it matches the left image? It seems a bit arbitary to me -- which prism to leave alone.


You are absolutely correct. THEY DO NOT TAKE THE AXLE INTO CONSIDERATION. AND IF YOU DO NOT TAKE THE AXLE INTO CONSIDERATION, THE ONLY 'COLLIMATION' YOU ARE GOING TO GET IS BY FLUKE. If "Conditional alignment" is all you need, you do not have to consider the axle.


As for me, I would rather have a Rolls than a Chevy.

Cheers,

Bill

#9 BillC

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Posted 30 July 2004 - 11:41 AM

I did find the following on a ATM list:

If you have a telescope ~8" or bigger, you already have a binocular collimator of sorts. Just put the binos in front of the scope, facing the scope. Mask off the scope so it sees only the binocs. The eyepieces should face a bright daylit target like the top of a power pole. Look thru the main scope & you'll see an image of the outside scene. If the binocs are not collimated you'll see a double image. To collimate you have to shift one or more of the prisms around until the images are merged in x, y, and roll. Tedious but not expensive (although I wouldn't build an 8" scope just for this purpose.


I have seen this before. However well intentioned, it is meaningless. Why?

1) If you have to build a collimator to be able to TELL your binocular is out of collimation, then your binocular is not misaligned enough to worry about in the first place.

2) Saying that you just move the prisms around until you get one image is technically accurate. However, it is as accurate as saying that all you need to do to get your airplane off the ground is to build an engine.

Just some thoughts,

Bill

PS The good news is that my bino book is 80% complete! The bad news is that it HAS BEEN 80% complete for several years!!!

#10 BillC

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Posted 30 July 2004 - 11:58 AM

>>>While it's no where near the level of accuracy that Bill Cook is talking about with those high zuit collimators, the book "Choosing, Using and Repairing Binoculars" by J.W.Seyfried contains a section on making a homemade binocular collimator out of parts available from a hardware store and from Surplus Shed.<<<

I have known Jan for almost 30 years. I like and respect him. However, I will stand by my S&T review of his book. I had hoped to see a corrected and updated 2nd edition by now.

Cheers,

Bill

#11 Guest_**DONOTDELETE**_*

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Posted 30 July 2004 - 05:52 PM


You are absolutely correct. THEY DO NOT TAKE THE AXLE INTO CONSIDERATION. AND IF YOU DO NOT TAKE THE AXLE INTO CONSIDERATION, THE ONLY 'COLLIMATION' YOU ARE GOING TO GET IS BY FLUKE. If "Conditional alignment" is all you need, you do not have to consider the axle.




Cheers,

Bill


Thanks Bill. That's what I thought. Most collimation instructions seem to speak in a such a vague way.

As for me, I would rather have a Rolls than a Chevy.


yeah, but I'd take a Ferarri over the Rolls. have a good one.


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