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Scope Checker Usage Caution

It causes a large poa shift,
Loose ocular/eyepiece lens causes a point of aim shift?

I disagree. Unless there is a parallax issue caused by a target range focus error.

With the objective lens group's target image focused in the reticle plane and aim point centered on the reticle center, the point of aim stays there regardless of the aiming eye viewing angle or crooked eyepiece. That's when there's zero parallax, anyway you look at it.

Loose objective lenses in something that will cause a POA and LOS shift.
 
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I think the eyepiece should be set to make reticle the sharpest possible and forget about the optical formula diopter stuff as it's not important when focussing ocular lenses for reticle being in perfect focus for the aiming eye's optical properties.

If you are the only test observer then by all means set the ocular to best suit your needed vision correction. For test protocols that require several observers, presetting the ocular to zero diopter has worked fine for us over many tests.

Field & Cave - thanks for the update!

Tom - For use by a single shooter, I see no reason for a "fast focus" non-locking diopter adjustment on the ocular (eyepiece). Seems to be a cheap "feature" to help sales over the interests of the customer.
 
For test protocols that require several observers, presetting the ocular to zero diopter has worked fine for us over many tests.
What's the zero point on an eyepiece (ocular) lenses that don't have a scale and zero point marked?

Does it matter if the scope reticle is out of focus for some users if it's set to zero?
 
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Not a bad idea Larry, but lasers have beam divergence and I would guess one that would stay precise enough at say 50 yards to see a 1/16 moa shift would be very expensive.

I wont be without a frozen scope and scope checker, ever. Its the biggest eye opener in this game.
They measure accurate over long distance That is why they are use in construction
 
For use by a single shooter, I see no reason for a "fast focus" non-locking diopter adjustment on the ocular (eyepiece). Seems to be a cheap "feature" to help sales over the interests of the customer.

I totally agree. I have played with the rear ocular adjustments a million times over the years on every scope I've owned that had them. It just seems like it doesnt do much except for eventually making the image blurry when I screw it out far enough. Even as my eyes get a little worse with age, it still doesnt seem to help. I always end up screwing the ocular focus all the way in tight and never touching it again.
 
Does it matter if the scope reticle is out of focus for some users if it's set to zero?

For the purpose of alignment of the frozen fixed scope to the target, not very much within the +/- 2 diopter typical range when doing scope POA or ring holding tests. However, for normal use in target shooting it is IMHO very critical.

What's the zero point on an eyepiece (ocular) lenses that don't have a scale and zero point marked?

For surprisingly high end high price scopes, Plan A and the easiest way has been to ask the manufacturer. Plan B is to find the center of the adjustment range which is usually close enough. Plan C is to have someone with 20/20 (6/6 for our metric fiends) [or corrected there to] vision adjust for best focus of the cross hairs which is very close.

Plan A samples of 0 diopter location from the nice folks at DEON

50x or 60x52 0D.jpg March 40, 50 and 60x52

36-55x EP-Zoom 0D.jpg March 36-55x52 EP-zoom
 
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Update on our frozen scope project.

In the interest of full disclosure, of our 3 man optics/test group, one of my associates was an optics engineer and for part of his working life was with a firm that did riflescopes. Consequently he has become the lead man on the frozen scope project and jumped in quite enthusiastically.

After disassembly and examination of the first donor scope, he is recommending that rather than attempting to freeze the erector assembly he would prefer to replace the erector cell and reticle mount with a sturdy fixed assembly. We are now considering wether to use the existing lenses or change to better lenses (ED and multicoated) and what reticle would best suite our intended use.
 
I don’t know why someone doesn’t make on with a laser
For the proof

I've been slow in responding your question while trying to provide a reasonable reply. By the way, of our three man optics testing group I'm the one with the relevant experience in laser and optical alignment system.

An applicable durable small dot projection laser would be the type I've used in an underground mine (salt in my case) and outdoor rail alignment. A similar current version:

L355x Laser.png

Note the 1.5" dot @1000feet or 0.9" @200yards and 0.45" @100yards and the serious price. The older ones like this that I've actually used were tough enough for the intended use you have suggested but at 100 or 200 yards the spot would be hard to see on a sunny day on a conventional target so a retro-reflective target surface (like your license plate) would be better.

Overall while possible it would be an expensive solution.
 
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I've been slow in responding your question while trying to provide a reasonable reply. By the way, of our three man optics testing group I'm the one with the relevant experience in laser and optical alignment system.

An applicable durable small dot projection laser would be the type I've used underground mine (salt in my case) and outdoor rail alignment. A similar current version:

View attachment 1085999

Note the 1.5" dot @1000feet or 0.9" @200yards and 0.45" @100yards and the serious price. The older ones like this that I've actually used were tough enough for the intended use you have suggested but at 100 or 200 yards the spot would be hard to see on a sunny day on a conventional target so a retro-reflective target surface (like your license plate) would be better.

Overall while possible it would be an expensive solution.
Looks like the answer isn’t cheep
But not as expensive as a scope
 
Looks like the answer isn’t cheep
But not as expensive as a scope

By the time you include the scope and the cost to freeze one it may be close to a tie. In our 3 man testing group we tend to treat our labor as $0/hr since that is what we get as all of us have been retired quite a long time.
 
By the time you include the scope and the cost to freeze one it may be close to a tie. In our 3 man testing group we tend to treat our labor as $0/hr since that is what we get as all of us have been retired quite a long time.
I thin the add. Weight and the weight of the with between could give different results I would trust a something that can’t move the something that can
 
A medium power, external adjustment Lyman, Fecker, Unertl or Di Simone fixed power scope would be great as a reference scope.
 
A medium power, external adjustment Lyman, Fecker, Unertl or Di Simone fixed power scope would be great as a reference scope.

Even if I still had one, I could not subject it to high recoil testing. I'm not sure it would survive and it is not easily replaceable or repairable.
 
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Update 1/31/19

Our optics guru has frozen one donor scope using its original erector with original lenses but with new etched fine cross hair reticle and new reticle mount. He is prepping mounts for the second donor which will include new ED erector lenses and a new fine etched cross wire reticle while awaiting the new lenses.

The remaining two of us are prepping target designs to use initially to test the two frozen scopes then mounts and other scopes for POA shifts. To that end, we would appreciate input as to what would constitute a minimum detectable POA shift. Please specify as 0.XXX MOA or 0.XXX inch at XXXX yards or X.XX millimeter at XXXX meters.
 
Update 1/31/19

Our optics guru has frozen one donor scope using its original erector with original lenses but with new etched fine cross hair reticle and new reticle mount. He is prepping mounts for the second donor which will include new ED erector lenses and a new fine etched cross wire reticle while awaiting the new lenses.

The remaining two of us are prepping target designs to use initially to test the two frozen scopes then mounts and other scopes for POA shifts. To that end, we would appreciate input as to what would constitute a minimum detectable POA shift. Please specify as 0.XXX MOA or 0.XXX inch at XXXX yards or X.XX millimeter at XXXX meters.


If human eyes can see it, it is too much. At least that's how I see it.

Tom
 
If human eyes can see it, it is too much. At least that's how I see it.

Tom - I agree with you in principal.

However, we are trying to devise a test protocol that will be both practical and useful. The limiting factor will be the nominal resolution of the scopes and vernier resolution in combination with the test targets. For example the ring tests our group did had a nominal resolution of 0.05 MOA (scope) and a vernier resolution (target/conditions) of 0.01 MOA. This means any POA movement had to be more than 0.01 MOA to be detectable under favorable conditions. Note that the size of the SRBR current record group is 0.00735 MOA so we are not yet able to detect a POA shift that size.
 
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