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Binocular FOV allignment

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#1 ngc 9999

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Posted 29 January 2013 - 10:50 AM

Hello,

I need help in aligning the FOV of my binoculars, I have them conditional aligned for merging stars but when looking through them, the overlapping FOV is quite distracting.

How can I align them sufficiently as not to be so distracting? I know that to merge stars, depending on the error, you need to move two screws of both barrels at the same time in order to maintain exit pupil shape, but I don't know how to do this with the barrels.

Thanks.

#2 Jawaid I. Abbasi

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Posted 29 January 2013 - 11:01 AM

IF I AM CORRECT THEN YOU HAVE NOW CONDITIONAL BUT WHEN LOOKING THROUGH, YU MAY SEE PARTIAL OVERLAP CIRCLES.

IF YOU HAVE AN OPTION FOR OBJECTIVE'S RING THEN CHECK RON HARPER NOTES AND STRT WORKING WITH RIGHT SIDE FIRST AND MAKE SURE THAT IPD SETS FIRST

#3 EdZ

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Posted 29 January 2013 - 11:49 AM

this is a classic case of having turned the wrong screws to achieve conditional alignment. You might try undoing what you did to go back, see if the field stops then realign. Then proceed to attempt conditional alignment by attacking some other screws, probably even a number of screws.

best advice would be to send them to someone who could realign them for you, not conditional alignment.

edz

#4 ngc 9999

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Posted 29 January 2013 - 06:18 PM

Which Ron Harper notes?

#5 daniel_h

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Posted 29 January 2013 - 06:39 PM

how can you move 2 crews on both barrels at the same time..doesnt this equal for screws your turing..hardest thing is to note which barrel is the mis-aligned one, in reference to the centre axis of the bino. turn the correct barrel screw & you've doubled your trouble

#6 ngc 9999

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Posted 29 January 2013 - 07:01 PM

Concerning the movement of two screws on both barrels at the same time, I read in Edz article about binocular collimation that you have to do that to avoid cat's eye exit pupil, like when you are collimating a SCT.

#7 EdZ

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Posted 29 January 2013 - 07:36 PM

you certainly don't need to do that at the same time, but little bits this, little bits that. Watch what's happening to the point sources merging at the same time you are watching what's happening to the field stops. If you are merging point sources, but throwing off the field of view, you are doing something wrong. (Not meant in any way to crack on you ngc 9999, but as a lesson to all readers).

The problem some people get into with conditional allignment is they pick a screw and work with it. Well, there are four screws, sometimes six screws. How in the hell do you know if you picked the right screw! And how do you know you can get the proper adjustment all with one screw without messing up something else!

Conditional alignment with one screw ain't all it's cracked up to be. Sometimes if it's a tiny bit needed, that's all you need to do. In those cases it's the perfect solution. But sometimes that's not all you need to do. Care must be taken to watch what you are doing.

#8 BillC

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Posted 29 January 2013 - 08:05 PM

If you have been turning screws on BOTH sides at once, I hate to report that you now have a soup sandwich and CoAl is the BEST you're gonna do.

If you would like some reading material on 3-axis collimation, just send your email address to:

wjc 1111 (at sign) hot mail dot com

Cheers,

BillC

PS If you're seeing a "cat's eye," your collimation is off . . . WAY OFF, or a baffle is out of place.

#9 ngc 9999

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Posted 29 January 2013 - 08:34 PM

There is not cat's eye in the pupil, but why now it takes more negative diopters than before doing merging to reach focus, from -0.5 to -5 in the right eye and from -0.5 to -4.5 in the left eye and tireness induced astigmatism? Maybe I'm staring too much at the computer?

#10 BillC

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Posted 29 January 2013 - 08:56 PM

Most, new to observing, don't stare enough! The brain wants things in focus . . . NOW! So, as the observer operates the focus, without just staring to let the bino do the work, the ciliary muscles push and pull the eyeball to make it so.

Then, when the eye gets tired of being in the uncomfortable position for a while, refocusing is required; quite often starting the process again.

BillC

#11 GlennLeDrew

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Posted 29 January 2013 - 09:26 PM

I suspect that the field stop circles were displaced before attempts at alignment. Without having done any kind of proper analysis, my feeling is that no matter how badly mucked up the true collimation is, if a conditional alignment is achieved then the field stops, if not displaced, should also overlap.

One way to test this is aim the bino at a completely featureless subject, such as a bare wall or the daytime sky. You *do not* want any kind if detail to gorce your eyes to merge a potentially misaligned pair if images. With eyes relaxed and mutually parallel, as soon as you peer into the eyepieces, how do the field stops appear relative to each other? Look away for a little tiwsrd some distant scene so as to 'reset' your eyes to parallelism and repeat.

If after several iterations you see that the field stops are offset, this is probably due to some degree of eyepiece tilt and/or actual field stop lateral displacement. This can be more likely with center focus mechanisms, and when the field stop is not part of the eyepiece itself, but rather is part of the barrel over which the eyepiece slides (center focus) or screws (individual focus.)

#12 BillC

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Posted 29 January 2013 - 09:33 PM

"then the field stops, if not displaced, should also overlap."

Or so nearly so it wouldn't be obtrusive. So many myths; so little time.

BillC

#13 ngc 9999

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Posted 29 January 2013 - 09:52 PM

Before attempting to do the merging of stars, there was no apparent field stop overlapping, but because I did the defocused star test to see if the stars were merged enough, the bright point was just touching the edge of the defocused star (I wonder if that affects double star viewing), then I proceeded to try to get a better merging to see if things would improved. Now fields of view are about half a degree from the actual field stop. I wonder how to reset it again.

#14 Jawaid I. Abbasi

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Posted 29 January 2013 - 11:27 PM

The bright star should be in the center of defocus star. Try to move the IPD and see if the bright star moves

#15 ngc 9999

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Posted 30 January 2013 - 09:09 AM

I was told that it doesn't necesarily has to be right in the center, if it's at least half way to the center it's ok.

#16 Gordon Rayner

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Posted 30 January 2013 - 01:10 PM

THE HINGE
has been neglected in this discussion. Its axis is the key to servicing this overadjusted/maladjusted binocular.

To return it to the situation where minor additional adjustment could be used to make the two optical axes parallel at one and only one interpupillary adjustment ( two-axis parallelism or "conditional alignment" ( where the two optical axes are not actually aligned (colinear), but are parallel ), at least one of the optical axes must first be adjusted to be at least nearly parallel to the hinge axis.

In the absence of a kit of industrial optical tooling paraphernalia, one could use:

A V-block, one of whose vees rides the hinge exterior. The other vee might hold a crosshair equipped sight tube, of the kind used in collimation ( in the true sense of that word) of a Newtonian telescope. The crosshair of the sight tube should be concentric with the outside of its cylindrical barrel. A good sight tube should should show little or no motion of the crosshair center position on a target when the tube is rotated in a firmly clamped vee block.

Or, the vee block might hold a small diameter metal tube, or a straight plastic drinking straw, to serve as a tubesight as was found on BB guns or rifles of the past.

With the binocular firmly clamped, a distant target can be positioned in the center of the sight, by moving a tripod mounted cardboard target. If the binocular can be pointed, and then locked, then towers, building features, flagpoles, steeples, bright lights, etc. are suitable fixed distant targets.

Adjust the screw(s) of one barrel until the target is centered in the field of view. Meanwhile, keep the target centered in the sighttube/tubesight. Repeat for the other barrel.

For fine adjustment into parallelism at your personal IPD, a reversed binoviewer, itself well adjusted, with its eyepieces removed , is a good comparison tool to see both images simultaneously. One could also use it to compare the image through one barrel to the tubesight/sighttube image of the target.

If the hinge exterior is inaccesible, then one could press the front of the bincular against a window (ff. the Fuji Photo Optical/Fujinon/Fujifilm UBMM ,in which gravity provides the push). That will make the hinge axis perpendicular to the inside surface of the window, within the limit of the assumption implicit in the construction of the UBMM : that the plane of the two barrels' fronts is perpendicular to the hinge axis.

A well-made vee block has ends which are at right angles to the axes of its vees. So, press the vee block and its sighttube/tubesight rider against the window, while a partner, or yourself, positions a tripod mounted target a city block ( or more, preferably,but not essentially,) distant.

The window mounted (pressed) binocular's hinge is thus pointed at the target.

Use of one of these techniques might result in a passable approximation to 3-axis parallelism, a.k.a. "collimation", or "3-axis alignment" ( which it is not, because the axes are not colinear), for use at all interpupillary distances.

#17 BillC

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Posted 30 January 2013 - 01:36 PM

If the bright star is at the EDGE of the fully defocused star, the binocular is, without a doubt, out of collimation and will affect double star observing.

“Now fields of view are about half a degree from the actual field stop. I wonder how to reset it again.”

I don’t understand—I don’t have to mindja. But, fields of view are inextricably attached to field stops.

One thing that might be helpful to remember is that the KEY concern should be the image and not the field stop, which may or may not be correct for a collimated bino.

Also, I don’t recall you stating which bino you’re discussing. And, it should not be supposed that all binos are created equal. Further, if you are not looking at an infinity target (The Navy has the power to shorten infinity to one nautical mile.) you are going to see the field stops as troublesome.

If one is looking at a distant object and notices—with peripheral vision—that the fields overlap, then an error in collimation is present. More often than not, the folks will look for collimation error by concentrating on the “circles.” When they do this, they’re focusing INSIDE the binocular. And what happens when you focus on something that close? You have to cross your eyes. And what happens when you cross your eyes? You start seeing double? And what do you THINK is wrong when you start seeing double? You think the binocular is out of alignment . . . when, in fact, YOU are!

Just more ramblings.

BillC

#18 Simon S

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Posted 30 January 2013 - 02:17 PM

I ask someone to try this experiment to see if they agree with me..
With a known correctly collimated binocular look at an object some distance away, say a roof edge that has a vertical and horizontal plane.
Move the binoculars away from your eyes bet keep the target in view. Now swing the binocular ipd through its full range, while watching the image through both eyes.
If the image shifts relative to the other the binocular is not collimated despite how it looks when in normal use.

All my binoculars that are new show no shift in position, however all my serviced binoculars show some deviation.
Bill, I know you are going to dismiss this "crazy hillbilly" idea but try it. Please!!!!!

#19 BillC

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Posted 30 January 2013 - 03:32 PM

You’re a Brit; you are not authorized to be a hillbilly!

“ALL MY BINOCULARS THAT ARE NEW SHOW NO SHIFT IN POSITION, HOWEVER ALL MY SERVICED BINOCULARS SHOW SOME DEVIATION.”

And what method are you using for collimation? It sounds like the best you are doing is CoAl.

“MOVE THE BINOCULARS AWAY FROM YOUR EYES BET KEEP THE TARGET IN VIEW. NOW SWING THE BINOCULAR IPD THROUGH ITS FULL RANGE, WHILE WATCHING THE IMAGE THROUGH BOTH EYES.”

Unless you have some incredibly weird eye sockets, that’s not going to be a happening thing—close but not clinical. YOUR personal IPD does not change; thus, your line of sight does. Think “angles.”

“IF THE IMAGE SHIFTS RELATIVE TO THE OTHER THE BINOCULAR IS NOT COLLIMATED DESPITE HOW IT LOOKS WHEN IN NORMAL USE.”

A Conditionally Aligned binocular MAY very well SEEM collimated because of your personal Spatial Accommodation. However, when you move the instrument away from your face that accommodation is accentuated and you are seeing the TREES and not the FOREST.

This is why so many people have told me their bino was “perfectly” collimated when it wasn’t.

"BILL, I KNOW YOU ARE GOING TO DISMISS THIS "CRAZY HILLBILLY" IDEA BUT TRY IT. PLEASE!!!!!"

Good and bad, all my binos are in the basement. Besides, I’ve seen what you’re talking about many times.

Did the above help or just muddy the water? If the latter, I’ll keep trying.

Cheers,

Bill

#20 Gordon Rayner

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Posted 30 January 2013 - 03:34 PM

That gives a rough idea of the situation for go/no go. But a well-adjusted, eyepieceless, reversed binoviewer ( or one of the JTII "hand collimator, or equivalent) gives an easier, more exact, assessment.

Be sure to keep the line between the pupils parallel to the horizontal line of the target.

#21 BillC

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Posted 30 January 2013 - 03:55 PM

Gordon:

Many are the times—including lately—you have asked CN members to just check out collimation with “the JTII "hand collimator, or equivalent.” Frankly, I don’t think most members know what one is, let alone have a selection lying around the house. That makes your “or equivalent” more intriguing.

Thus, within the mileage and dollars of the average observer, could you please, briefly state what you perceive that “equivalent” to be. Is it something readily available? At what store is the "JTII hand collimator" available-- should one want a unit--and how much does one cost?

BillC

#22 Mark9473

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Posted 30 January 2013 - 04:17 PM

I was told that it doesn't necesarily has to be right in the center, if it's at least half way to the center it's ok.

I agree with that, especially if it's mostly horizontal displacement.

#23 ngc 9999

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Posted 30 January 2013 - 06:54 PM

[quote name="BillC"]

“Now fields of view are about half a degree from the actual field stop. I wonder how to reset it again.”

I don’t understand—I don’t have to mindja. But, fields of view are inextricably attached to field stops.''

What I mean is when I look at a distant target the two barrels field of view have some degree of overlapping.

I have the Garrett SS 10x50 binoculars.

#24 ngc 9999

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Posted 30 January 2013 - 06:56 PM

[quote)

“Now fields of view are about half a degree from the actual field stop. I wonder how to reset it again.”

I don’t understand—I don’t have to mindja. But, fields of view are inextricably attached to field stops.
[/quote]

#25 ngc 9999

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Posted 30 January 2013 - 07:01 PM

What I mean is when I look at a distant target I see a considerable degree of field of view misalignment, which seems that with minor tweaking can be corrected. And my binoculars are 10x50 Garrett SS. I emailed Garrett and he sent me the intructions.






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