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#26 beachchairbill

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Posted 14 September 2010 - 04:14 PM

Rich V.

Your right on the money. I removed both focuser turrets late last night and noted that I did not screw on the the left turret screw properly and that made the difference. After I properly screwed oon the turret and their is a nack to it I rechecked the laser dot and it was back to where it as off originaly. WOW, sure glad I did not make any adjustments before I doubled checked. As they say " measure twice and cut once". Bill will check three times and move once and then check again.

I have noted with the GBT that you have to make your adjustment and then put the focuser turret back on and then check your movement if any. This is like playing chess.

Talking about screws, which screw is the push screw and which screw is the pull screw or large screw small screw rusty screw which on does what?

Also, if you look at the pictures and are ready to make the small adjustment whic screws would you turn first.

Looking from the focuser end the laser shows that I am off center by about a quarter of an inch down and to the right on both sides from center. Which screws get turned first?

I think it should be the left screw turned to the right about a quarter turn? What does everone think?

Don't forget I have to take the focuser turret off again, make my adjustment and then put it back on again and then check it with the laser.

EDZ thanks for adding to this thread and it's good to see that you stay in the loop.

Erik D. are you back from vaciation yet?

Thanks

BB - DCW

#27 Rich V.

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Posted 14 September 2010 - 05:36 PM

Bill, the larger screw should be the pull screw; for either barrel, first I'd try backing off the smaller push screw at the 2:00 position as you look at the prism. You will then have to tighten the pull screw to lock the prism down again. Just a little at a time and keep track of your adjustments.

Once you're satisfied that the left barrel is centered on axis leave it alone and do the same for the right side. Now check for collimation by the "eyeball test" and if the misalignment is small you can collimate the barrels by only adjusting the right side. Since you must remove the right side turret first anyway, its easier to collimate just by adjusting the right side. My instructions explain all this.

Hopefully, you'll get the binoculars collimated to your satisfaction and when you put the laser in the focusers, the laser dot will be very close to the center dot on your target on both sides. Don't expect both sides to be perfect as there could easily by a bit of mechanical misalignment between the barrels. The right side will have to be compromised by a bit of prism tilt to make up for this misalignment.

EdZ, since the collimation convention with these binoculars is tilting the main 45° prism, not the turret prisms, rotation of the fixed rhomboid prism turrets shouldn't effect collimation assuming that the binoculars have been assembled correctly at the factory with both turrets aligned and parallel. Of course, I can't say this is absolutely the case. In theory, anyway. ;)

Rich V

#28 beachchairbill

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Posted 14 September 2010 - 06:24 PM

Rich V.

That was a mouth full and a great help. I will take a deep breath and try this tomorrow or late tonight. Coaching HS Swimming tonight.

Thanks Rich

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#29 Mr. Bill

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Posted 14 September 2010 - 07:14 PM

Ah grasshopper....the beginning of wisdom....step one, it ain't magic to take things apart to figure it out.

Good for you

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#30 Gordon Rayner

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Posted 14 September 2010 - 09:12 PM

One could put the laser into the eyepiece holder, then rotate the rhomboid housing through a large angle, to see the beam describe an arc on a target placed ahead of the objective lens. By repeated adjustments ( which in this case seem to require removal of the eyepiece holder, at each interation,for access to the rhomboid prism(?) (where are the Schmidt prism adjustment screws( tilt fore-aft ,and/or laterally )if any?) adjustment screws, ), the radius of the arc could be shrunk to close to zero.

Repetition of this process on the other side of the binocular would result in alignment for all interpupillary distances. Fortunately in practice, the arcs' angles change, during IPD changes, by much smaller amounts in a two-hinge system such as this one, than they do for corresponding changes in interpupillary distance on a single hinge binocular such as most handhelds. So it is usual practice not to disconnect the link and swing arcs on dual pivot binoculars such as the Fuji 15 x 80 or 25 x 150, or the Nikon 20 x 120, or similar constructions, unless gross errors are suspected in the positioning of the prism clusters.

On the WW II Japanese 20 x 120 x 3 deg, with 45 degree inclination of the line of sight,and their USN copies, Schmidt prism ( light cone split ( Mode I)) plus rhomboid, the prisms are not adjustable. The alignment is via eccentric rings around eccentric objective lens cells.

I have no experience in adjustment of the Miyauchi designs or their clones.

#31 Rich V.

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Posted 15 September 2010 - 11:16 AM

Gordon, I agree. Do you think the three screws in the slotted plate on the back of the rhomb turret are for fine tilt adjustment of the rhomb?

I haven't fooled with the turret prisms as I've had no problems with Miyauchi's original calibration. With all the "clones" like Bill's out there now I suppose someone will have to play with that aspect as well sometime...........

Rich V

#32 GlennLeDrew

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Posted 15 September 2010 - 12:52 PM

Rich,
Those slotted triplet of screws on the underside of the rhomboid prism appear to me like they do not tilt the rhomb, but rather rotate it. This would then simply translate the optical axis laterally rather than alter its emergent angle, i.e., tilt.

#33 beachchairbill

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Posted 15 September 2010 - 01:24 PM

WOW,

Some of this information has gotten a little heavy for us rookies and I'm the guy behind the screw driver.

However thanks for the comments and makes for an interesting thread.

Rich I have moved the 1:30 screws as instructed and have moved the laser closer to the center point, however the larger of the two screws are getting very tight and I don't want to go any further without additional advice. Should I push the 10 o'clock screws a little and back off the 1:30 screws or?

Thanks

Beachchairbill

#34 Rich V.

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Posted 15 September 2010 - 01:47 PM

Bill, for any OUT movement of the push screw there must be a corresponding tightening of the adjacent pull screw and vice versa. Since the screws are brass they cannot take being over tightened; I found with the Miyas that it was easier to back off ALL the pull screws a fraction of a turn first to take the pressure off the push screws. I then made the push adjustment (either in or out) and re-tightened the pull screws to set the prism again. This will prevent the pull screws of the other two push-pull sets from becoming over tightened as you adjust the third set.

Understand that the prism is actually resting on the tips of the push screws creating a three point suspension. The larger pull screws just hold the prism tight against those three points.

The last thing you need is a snapped off screw; easy does it on the torque!

Rich V

#35 Rich V.

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Posted 15 September 2010 - 01:55 PM

Rich,
Those slotted triplet of screws on the underside of the rhomboid prism appear to me like they do not tilt the rhomb, but rather rotate it. This would then simply translate the optical axis laterally rather than alter its emergent angle, i.e., tilt.


That's what I thought at first but looking at the slots, only one is concentric with the axis of rotation; the other two slots are 90° opposed to it. It just didn't look right to me. I suppose there's enough slop in the two other slots where some movement could be made.....

The Miyauchi rhombs don't have slots at all.

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#36 beachchairbill

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Posted 15 September 2010 - 07:35 PM

Rich V.

Here is where I'm at right now.

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#37 beachchairbill

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Posted 15 September 2010 - 07:43 PM

The center is marked with a dot and the laser is marked with a circle on each side. Progress is being made, however, the push screw at 1: 30 the left can not go any further. Hope to get the laser dots a little closer to center.

Beachchairbill

#38 Rich V.

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Posted 15 September 2010 - 08:15 PM

If that's the case, now you need to go a bit in the opposite direction with each pair of screws on the opposite side. A little bit on each to keep the dot moving evenly towards center without vertical displacement. Make sure you loosen both pull screws a bit first before turning the push screws in.

It's kind of like leveling a tripod with a bubble level by adjusting leg length; some give, some take, depending on which side you are working from. The bubble is your laser dot. :)

Keep up the good work!

Rich V

#39 beachchairbill

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Posted 15 September 2010 - 10:11 PM

Rich V.

Thanks for the directions, where close to the finish line.

BB

#40 Gordon Rayner

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Posted 15 September 2010 - 11:43 PM

What would be the purpose of that? To center the rhombs with respect to the eyepieces?

#41 Gordon Rayner

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Posted 15 September 2010 - 11:50 PM

I do not have enough pictures( nor do I have any experience with these) to form other than a guess about the function of the three screws or screw pairs.

#42 beachchairbill

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Posted 16 September 2010 - 12:45 AM

To start I'm looking at centering the center of the eyepiece with the center of the objective lense and we will take it from there.

BB

#43 beachchairbill

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Posted 16 September 2010 - 12:57 AM

Rich V.

I have now centered the left side, however I'm a tiny bit heigh. Do I use the bottom push - pull screws to bring the laser down and if so which way left or right to go down.

I have also noted that after taking two focusers screws on and off several times I can now do it in seconds. For the recored I have removed and placed them back 10 times already.

BB

Thanks

BB

#44 beachchairbill

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Posted 17 September 2010 - 12:15 AM

Hi everyone,

Houston we have a problem.

Found that one of the push screws on the right tube was broken and stuck in place with hot glue. Not on my watch. Any ideas on how I should get the rest of the screw out. I would not prefer to use the other tri push pull screws to take on additional work.

Are their ways to remove the remainders of this screw.


Beachchairbill

#45 EdZ

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Posted 17 September 2010 - 05:38 AM

To start I'm looking at centering the center of the eyepiece with the center of the objective lense and we will take it from there.

BB


You may be attempting this in vain. It is quite possibble that in order for the images to be merged those projected laser spots, in one or the other side NEED to be slightly off the center.

Have you set up and observed point sources for merging after these adjustments?

edz

#46 Rich V.

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Posted 17 September 2010 - 10:44 AM

Like we talked about in PM, and EdZ has reiterated, you've probably got the optical axes close enough to center now. You need to put the binoculars together and check to see how far one side must be moved to merge with the other. There is almost a certainty that you will have to tweak one side or the other to get the images collimated anyway. It's just unfortunate that it's the right tube that's given you problems as that would have been the easier tube to adjust due to the disassembly order of the turrets.

Give it the "eyeball collimation test" on a distant target and see just see how the tubes align with each other. Hopefully a small adjustment of either side will merge the images and you can put this to rest.

Rich V

#47 beachchairbill

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Posted 17 September 2010 - 04:01 PM

Ed, Rich,

Give me a distance and I will give it a try on the weekend.

I also have Jupiter out my kitchen window and could use it as well.

I was able to remove the broken screw and replace it, however the right side is still not to my liking. Once their I will take your advice and wrap this up. I'm tired of tanking the focuser on and off and on and off and on and off to the point that I have blisters on my fingers.

Thanks for your support.

Beachchairbill

#48 Rich V.

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Posted 17 September 2010 - 04:35 PM

Ed, Rich,

Give me a distance and I will give it a try on the weekend.


Bill, the farther the target is, the better; I like to set up on a distant fixed target and the Home Depot five miles across the valley from me has some wall pack lights that work just fine from my open den window. Planets and bright stars are great but they keep moving!

Remember, don't collimate while looking through a glass window! ;)

Glad you were able to get the snapped screw out. Someone in a shop somewhere (not pointing fingers here!) must have had a really bad day, hence the oddball rusty phillips push screw also on the right side. I don't think the factory would have sent it out that way but who knows......

Rich V

#49 Mr. Bill

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Posted 17 September 2010 - 06:43 PM

Glad you were able to get the snapped screw out. Someone in a shop somewhere (not pointing fingers here!) must have had a really bad day, hence the oddball rusty phillips push screw also on the right side. I don't think the factory would have sent it out that way but who knows......

Rich V


This is interesting.....these were sent back for repair/collimation, am I correct?

:question:

#50 beachchairbill

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Posted 17 September 2010 - 08:24 PM

Mr. Bill,

Yep and I forced them to take them back - I just mailed them back with a note at my expense.

Rich,

I have just the place about a half mile away. Will give them a look see tomorrow.

Thanks

BB


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