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Help.....I'm seeing double!

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#1 Guest_**DONOTDELETE**_*

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Posted 12 July 2004 - 10:26 PM

I am seeing double though my 20x100s. Does this mean there is a problem with the instrument or the user?

#2 jwaldo

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Posted 12 July 2004 - 11:18 PM

It's the binos. They're miscollimated, and will need to be recollimated- which I know nothing about :|. Someone more knowledgeable will be along soon...

#3 EdZ

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Posted 13 July 2004 - 05:50 AM

Read the "Best Of" threads for several links to articles and instructions on collimation.

edz

#4 Guest_**DONOTDELETE**_*

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Posted 13 July 2004 - 11:04 AM

there is a how to collimate on Oberwerk site under support as well. that works on thier 22x100. It is what I followed to collimate my 15x70 celestron skymasters. Not sure which binos you have but it may help.

Essentially there are two screws. One for each prism tightening the right on move the right optic down and to the left, tightening the screw on the left side moves the left optic down and to the right. One mine the screws were on the top towards the outside of the section that holds the prism. I needed to lift the plastic to see them.

#5 EdZ

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Posted 13 July 2004 - 11:48 AM

There is a screw for each of the two prisms in each barrel. So there are four screws. Rarely do people look for the front prism screws under the rubber coating. Most just look for the back (eyepiece end) prism screws. Truly, you would be at a loss to try to determine which prism has moved. So just go for the back screws and hope you get it right.

Definitely read the links provided before you do anything.

edz

#6 Guest_**DONOTDELETE**_*

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Posted 14 July 2004 - 08:53 AM

Thanks! I'll let you know how it turns out.

Maybe I'll write an article: "Technically Challenged Social Scientist Attempts Fine Adjustment"

#7 BillC

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Posted 19 July 2004 - 12:26 AM

Several conventions are currently being used in binocular collimation. The best uses eccentric rings on the objective (Fujinon FMTR, MTR, Nikon Astrolux & ProStar). The fastest uses three large adjusting screws that can be reached through the metal or plastic backplates (Fujinon AR, XL, Swift Seahawk). The worst method—and of course the most common—is that which has screws in the top rear of each telescope and the inner front of each telescope. These can be a pain to find without some trial and error and, more often than not, there is not enough back-pressure on the flat springs.

[Another method popular on some smaller roof-prism instruments is to have adjusting screws under the E.P. cover.]

Most of the 11x80’s and 20x80 have three TINY screws around the objective so that lateral motion can be attained. This is a lousy way to run a railroad and explains why more than half of this genre of instruments arrive in the stores out of collimation, already.

“Conditional alignment” is what most amateurs achieve when they “collimate” their binocular.

True collimation is only attained if the both telescopes are aligned to the axle AND each other. Conditional alignment means that at some given IPD collimation falls with industry standard, JTII standard, MILSpec, or some other standard.

Unfortunately, I do not have time at the moment to go into all the details of collimation. However, the full description is available in the US Navy’s “Opticalman 3 & 3” which is now being sold under a civilian cover titled “Optics and Optical Instruments.”

Finally, there are those who profess to be able to look backwards through a bino and tell which is the offending side. Yes, if the bino is looking into two counties (shires, provinces, or parishes) at the same time, they certainly can tell—but then, so could Lassie. However, a binocular might be out of collimation several times industry standard and not show a problem to the TRAINED eye with this method.

Still, let’s not give up hope. More than likely, when a bino is out of alignment, one side is the greatest part of the problem. So, looking backwards through the instrument (looking for concentric circles of lenses and stops) MAY tell you which telescope needs the attention. It is better to work on the offending side than to screw up the other as well.

Just some thoughts,

Bill

#8 Guest_**DONOTDELETE**_*

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Posted 24 July 2004 - 01:04 PM

I think I just got incredibly lucky. My jeweler's screwdrives came in the mail, so I set up my binos and to adjust them as recommended by Ed (and Jason at apogee). I focused on a stick a block away, and clearly saw two sticks. I stuck the screwdriver in one of the holes and turned ever so slighly. I looked again--one stick.

So I think I am ready to go. More T-storms this weekend in Oklahoma, so I'll have to wait to test them under clear skies.

Thanks, again, Ed for the time you spend helping us.

#9 BillC

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Posted 24 July 2004 - 04:50 PM

I think I just got incredibly lucky. My jeweler's screwdrives came in the mail, so I set up my binos and to adjust them as recommended by Ed (and Jason at apogee). I focused on a stick a block away, and clearly saw two sticks. I stuck the screwdriver in one of the holes and turned ever so slighly. I looked again--one stick.

So I think I am ready to go. More T-storms this weekend in Oklahoma, so I'll have to wait to test them under clear skies.


Sometimes that is ALL that is necessary to perform conditional alignment, and if you have an inexpensive bino or no collimator--and most folks don't have one laying around the house--it can be just fine.

However, take the same concept you just used and look a stick--let's make it a tree or power pole at least a mile away, and do the same thing. A BLOCK IS TOO CLOSE.

Then, pull back about 4 inches from the bino and just STARE. If you are close, and you allow it, the brain will force the muscles around your eyes to align for you. This is NOT good, especially for viewing over long periods of time.

If, with the target at a distance greater than a mile, and with you pulling back 4+ inches, and with you just staring, you have one image, life is good--AT LEAST AT THAT PARTICULAR IPD.

Just a thought,

Bill


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