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Posted: 3/14/2016 9:07:55 PM EDT
| What is collimator when referring to a Bino set and how is it done? |
| I understand it as actually the same way you adjust regular binoculars by bringing the eyepieces closer together so that the image from each tube is merged into one in your vision. The Mod Amory bridge I'm using for the moment is very similar to adjusting collimation as you would with regular binoculars. On dedicated nv binos the process is the same but with a different mechanism to align what you see in the tubes so the individual images appear to merge. Someone will be along to correct me if I've not given you good info, but that's how I currently understand it. |
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Collimation means different things - At the core, the word basically means to make the rays of light passing through a point more parallel. In a PVS-7, it means to align the lenses so that the vertical alignment of the split image is equal. In an AVS-6, it means to adjust the oculars so that they have the same magnification when at at the same optical correction, so that your eyes are both focused for the same distance as they would be without the NOD. It does not, however, mean to align the optical axis of each image. In the PVS-22, it means to align the optical axis of each image also. (aka, boresighting). In a clip-on, it means to boresight it. Quadeyes are another form of collimation yet again. Regards David |
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Collimation means different things - At the core, the word basically means to make the rays of light passing through a point more parallel. In a PVS-7, it means to align the lenses so that the vertical alignment of the split image is equal. In an AVS-6, it means to adjust the oculars so that they have the same magnification when at at the same optical correction, so that your eyes are both focused for the same distance as they would be without the NOD. It does not, however, mean to align the optical axis of each image. In the PVS-22, it means to align the optical axis of each image also. (aka, boresighting). In a clip-on, it means to boresight it. Quadeyes are another form of collimation yet again. Regards David Great response. Now even I have a better understanding. Gotta love this forum. |
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In an AVS-6, it means to adjust the oculars so that they have the same magnification when at at the same optical correction, so that your eyes are both focused for the same distance as they would be without the NOD. It does not, however, mean to align the optical axis of each image. Regards David On the AN/AVS-6/9 the optical axis of the eyepiece lens is not the mechanical axis of the assembly, thus as you screw the assembly on the image moves. Colimation is aligning the two images. Normally this is done with a Hoffman ANV-126 Test set and collimation bridge. Setting the magnification the same is part of it, but you also have to align the two images. |
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On the AN/AVS-6/9 the optical axis of the eyepiece lens is not the mechanical axis of the assembly, thus as you screw the assembly on the image moves. Colimation is aligning the two images. Normally this is done with a Hoffman ANV-126 Test set and collimation bridge. Setting the magnification the same is part of it, but you also have to align the two images. Quoted:
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In an AVS-6, it means to adjust the oculars so that they have the same magnification when at at the same optical correction, so that your eyes are both focused for the same distance as they would be without the NOD. It does not, however, mean to align the optical axis of each image. Regards David On the AN/AVS-6/9 the optical axis of the eyepiece lens is not the mechanical axis of the assembly, thus as you screw the assembly on the image moves. Colimation is aligning the two images. Normally this is done with a Hoffman ANV-126 Test set and collimation bridge. Setting the magnification the same is part of it, but you also have to align the two images. And is it not today applicable to any binos that use PVS-14 eyepieces too? Or at least some newer PVS-14 eyepieces as I understood that they are the one and the same with AVS-6/9 nowadays. Remember reading about this when I noticed that stars rotate a small circle when I rotated my MUM and then came the thought of collimating two of them. Nivisys said to shim the tubes with electric tape 
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Quoted: And is it not today applicable to any binos that use PVS-14 eyepieces too? Or at least some newer PVS-14 eyepieces as I understood that they are the one and the same with AVS-6/9 nowadays. Remember reading about this when I noticed that stars rotate a small circle when I rotated my MUM and then came the thought of collimating two of them. Nivisys said to shim the tubes with electric tape Quoted: Quoted: Quoted: In an AVS-6, it means to adjust the oculars so that they have the same magnification when at at the same optical correction, so that your eyes are both focused for the same distance as they would be without the NOD. It does not, however, mean to align the optical axis of each image. Regards David On the AN/AVS-6/9 the optical axis of the eyepiece lens is not the mechanical axis of the assembly, thus as you screw the assembly on the image moves. Colimation is aligning the two images. Normally this is done with a Hoffman ANV-126 Test set and collimation bridge. Setting the magnification the same is part of it, but you also have to align the two images. And is it not today applicable to any binos that use PVS-14 eyepieces too? Or at least some newer PVS-14 eyepieces as I understood that they are the one and the same with AVS-6/9 nowadays. Remember reading about this when I noticed that stars rotate a small circle when I rotated my MUM and then came the thought of collimating two of them. Nivisys said to shim the tubes with electric tape The collimation processes for the ANVIS series only relates to the eyepiece in all models that I am aware? NVGdude, can you confirm? I realize there's some image movement, but it's not boresighted - that is, there's no optical axis correction or compensation for either the objective or the image intensifier that I am aware of - not that I've ever had much of a play with them. Also the allowed 1 degree error in collimation is kind of large IMO - a bit like missing the broad side of a barn if there was any other collimation system within the housing. And yes, you can collimate dual PVS-14s and that's kind of the same - I expect you could use the same tester and collimation bridge as for the ANVIS ( again, I've never tried it, so there may be mechanical interference ) - But the off-axis specification for the MX11769 is way looser than the MX10160 - something on the order of 2.5x IIRC, and I've seen some on the order of 4x out - and I have no idea how they managed to assemble them that badly. As a result, collimating them is going to be a whole lot more difficult, not to mention there's not much space to shim them, but yes, it is possible. Or you can build a PVS-14 with boresight correction internally to adjust for this error and then the whole thing is perfectly collimated end-to-end even if it's wonky on your face - Two of those would be close to perfectly collimated even if you managed to mount them at different angles. The boresight collimation process can even be done to a single monocular - though there is optical distortion off-axis, and the quality of the outcome would depend on how closely the focal lenses of the objective and ocular were matched. It also wouldn't matter if the tubes weren't matched then. Regards David |
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The collimation processes for the ANVIS series only relates to the eyepiece in all models that I am aware? NVGdude, can you confirm? But the off-axis specification for the MX11769 is way looser than the MX10160 - something on the order of 2.5x IIRC, and I've seen some on the order of 4x out - and I have no idea how they managed to assemble them that badly. As a result, collimating them is going to be a whole lot more difficult, not to mention there's not much space to shim them, but yes, it is possible. Regards David Wow, that is huge. Not knowing how much the PVS-14 / Anvis eyepiece actually allows you to "rotate" the axis, but remembering seeing the guide for Anvis collilmation it did not seem like it's much. Also true as far as I understand they would not be boresight collimated, just that that the images overlap, but they could be both shifted to any direction. Only to lessen eyestrain I guess. From that document I remember it is only the eyepieces (why I didn't save it, I don't know), so I guess that confirms what you asked. |
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Quoted: I think David is talking about setting the diopter. Not quite, though you'd be forgiven for thinking it's the same - It's about trying to get both eyes to see the same image, and Murtis described it pretty well. In the case of binoculars, you want parallel rays entering from the image direction to come out of the ocular lenses still parallel. Otherwise your eyes have to do too much work to correct the images - Of course, this is going to happen in most cases, but so long as it's less than 1 degree difference between left and right monoculars, it's generally considered to be collimated. Modern binocs would typically come in under 0.5 degrees. It's also for this reason that tubes are usually chosen in pairs for binoculars, since the collimation process usually only happens at the ocular end. By the time you've collimated and corrected the entire monocular, it's boresighted. PVS-22 are boresighted like this, and align both the real and intensified image. They have to move the tube around during manufacture to set this, then they fill the monocular with elastomer at that point - Quite an involved process. But although we don't hear about them much lately, the PVS-22 are a very special kind of NOD - Also, if you take any monocular and fully collimate it front to rear, and you don't need binocs, you can collimate just a monocular front-to-rear. Well, the result is that you can then stick it in front of a day optic and your POI won't shift - or at least, not by much - Usually 1 MOA or so. So a fully collimated monocular ( or boresighted ) will have around 1/60th of the maximum divergence from parallel that a Milspect AVS-6 can have. It always blows my mind that these monoculars in a binocular system can be so far out, yet our brains an still take that information, correct it and create a functional 3D image from it - Consider also that experienced instinctive shooters ( point shooting ) can often regularly hit targets within 3 to 10 MOA of where they are aiming. That's just anecdotal, and I could be wrong on the figure, but I recall some amazing accuracy at times. Anyway, that's way less than a degree. So if they shoot with a PVS-22, they will hit the target. But with AVS-6? They might miss it completely. Anyway, the point is, in many NV systems, the collimation is very limited and in many binocular systems ( and bi-ocular ) it's often just a case of bringing it within acceptable levels so the brain can use the image without causing too much load on the brain, which can lead to headaches and nausea. If you want to measure collimation error without a hoffman tester, or parallel rays from two images, use a bench-fixed riflescope and a target image marked in degrees calculated for the range it sits from the riflescope. Then just put the monocular in front of the riflescope and read off the shift in the aim as the collimation error. For binocs, read both, and work out the difference between then. If you ever find an AVS-6 with both sides within a few MOA, keep it :) That would be a very nice set. Regards David |
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In an AVS-6, it means to adjust the oculars so that they have the same magnification when at at the same optical correction, so that your eyes are both focused for the same distance as they would be without the NOD. It does not, however, mean to align the optical axis of each image. Regards David This sounds just like diopter ^^^ that's your post I was referring to. |
| I'm using a Mod Armory bridge for a little while. I haven't had to do anything but align each tube to my eye by hand and ensure the diopter is gives me the same image through both. My brain does the rest and I've had no issues with the images merging together in my vision. I've used the setup for a max continuous of about 6hrs one night and didn't get any headaches or eye strain other than what was caused by the weight. I would think the weight would be more of an issue before collimation running dual pvs-14s, as our brains are pretty good at merging a similar image, but I guess we could all be different in that respect. I added a decent amount more counterweight than when just using a mono and that's helped a lot. I truly had no idea that propper collimation was such a technical task. I guess it's benefits haven't been needed by me quite yet in my method of use. |
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I have never personally used a PVS-14 binocular, but knowing their oculars have collimation adjustment, off-axis lenses to shift the image, and Davids info that MX11769 tubes have a lot more room for error collimation than with MX10160's, in a worst case a dual PVS-14 could have the oculars and tubes at the words possible locations to give a huge difference in image location.
Our eyes are pretty good of forming stereo images from anything, but as an example some of us cannot see stereograms, meaning we do differ in the ability to form images from something that is not natural, like badly offset bino images. Another example is that for some time I had hard time forming a stereo image when using a monocular and actually closed my unaided eye in certain situations to make it easier to see. I'm sure there are individuals that can never merge NV and unaided views (when it's darker than moon being out), and ones to whom it is second nature from the get go. To the actual question, how would one do it without the beam splitter & tester. A rig of some sort where you have a riflescope or a camera firmly attached to something, some means of attaching either side of the binos directly and repeatably in the same position in front of the scope / camera and then looking through the scope / taking a picture with the camera and taking notes of the differences in image shift. A LED light or some other pinpoint light at a long distance (I would guess 100 meters is fine), and in the center of the scope view would help immensely. First you would need to figure out how the images shift when you rotate the eyepiece optic assy, so it would take a few tests before you could start making educated adjustments. After that is figured out, look at the differences between the images in both sides, and try guess how much you need to turn each to bring the images closer to each other. The images will rotate in a circle, so in my understanding there will be exactly two different settings that lead to a collimated view, assuming the differences in the tubes is less than the amount a PVS-14 ocular allows to move the image. In worst case there is no overlap points, but bringing them as close as possible is good anyway. A pretty tedious task without the proper tools.. And certainly not as accurate. Edit: and to give the correct answer, send them to someone who has the skills and the proper tools
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Quoted: Edit: and to give the correct answer, send them to someone who has the skills and the proper tools I think you are over-estimating the accuracy of the procedure - There is no prism inherent in the ANVIS ocular. Anyway, the simple version of the process for do-at-home is quite simple. This either works, or it doesn't. Get a large aperture camera with a good magnification and focus it on the stars, or at least at 100m to infinity - not any closer. Fix it somewhere if you can - with extra magnification if possible, and manual lens setting. Focus it, so that the lens stays fixed. Now use a big screen to view the video from it. Then with a well focussed monocular ( get it about as right as you can ) - looking at the same image, put the monocular in front of the camera with the diopter set to zero. Leaving the diopter at zero, rotate the lens assembly until it's in perfect focus - Note: The camera lens objective must have a fast lens and a reasonable aperture. OK, now you're done. Mark it with a marker pen, and an aligning mark on the housing. Finished ! Yes, I know this doesn't sound like collimating, and it isn't, but it's close enough to achieving the same result that you will probably get away with it within acceptable limits. If you find it feels a bit out, try rotating it up to a half turn in either direction ( with the ocular set at zero, though if you're doing this part by eye, select your correct diopter ) and see if it's any better - Generally, it won't be. As I said, not quite the same process, but it should get pretty close. Otherwise you'll need to set up a jig for collimating it properly - and remember that MX11769's are a lot further out typically than MX10160's. David. |
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Would that set the magnification, but not "collimate" the two monoculars together? The off-axis optical assembly could be anywhere, better or worse than where you started.
Edit: you could be right that I'm overestimating how much the optical axis is off-center and I actually don't even understand the effect of it completely.. Missed a few lines from your post too, so disregard the above, you didn't even mean to write a guide how to collimate. On top of all this, I have yet to bump into a comment saying their whatever-bino upgraded from two PVS-14 or dual PVS-14 is giving them headaches due to collimation, so I yeah probably the effect is smaller that I though. For aviation it's understandable, and a PVS-14 wasn't originally meant to be used in a bino setup. An image of what happens. Despite there being no prism the images do shift pretty noticeably, though it's impossible to know what kind of adjustments he made, one additional pic with the maximum error set in would have told a lot in this case: Image from Wilcox-res.com 
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I think you are over-estimating the accuracy of the procedure - There is no prism inherent in the ANVIS ocular. Anyway, the simple version of the process for do-at-home is quite simple. This either works, or it doesn't. Get a large aperture camera with a good magnification and focus it on the stars, or at least at 100m to infinity - not any closer. Fix it somewhere if you can - with extra magnification if possible, and manual lens setting. Focus it, so that the lens stays fixed. Now use a big screen to view the video from it. Then with a well focussed monocular ( get it about as right as you can ) - looking at the same image, put the monocular in front of the camera with the diopter set to zero. Leaving the diopter at zero, rotate the lens assembly until it's in perfect focus - Note: The camera lens objective must have a fast lens and a reasonable aperture. OK, now you're done. Mark it with a marker pen, and an aligning mark on the housing. Finished ! Yes, I know this doesn't sound like collimating, and it isn't, but it's close enough to achieving the same result that you will probably get away with it within acceptable limits. If you find it feels a bit out, try rotating it up to a half turn in either direction ( with the ocular set at zero, though if you're doing this part by eye, select your correct diopter ) and see if it's any better - Generally, it won't be. As I said, not quite the same process, but it should get pretty close. Otherwise you'll need to set up a jig for collimating it properly - and remember that MX11769's are a lot further out typically than MX10160's. David. Quoted:
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Edit: and to give the correct answer, send them to someone who has the skills and the proper tools I think you are over-estimating the accuracy of the procedure - There is no prism inherent in the ANVIS ocular. Anyway, the simple version of the process for do-at-home is quite simple. This either works, or it doesn't. Get a large aperture camera with a good magnification and focus it on the stars, or at least at 100m to infinity - not any closer. Fix it somewhere if you can - with extra magnification if possible, and manual lens setting. Focus it, so that the lens stays fixed. Now use a big screen to view the video from it. Then with a well focussed monocular ( get it about as right as you can ) - looking at the same image, put the monocular in front of the camera with the diopter set to zero. Leaving the diopter at zero, rotate the lens assembly until it's in perfect focus - Note: The camera lens objective must have a fast lens and a reasonable aperture. OK, now you're done. Mark it with a marker pen, and an aligning mark on the housing. Finished ! Yes, I know this doesn't sound like collimating, and it isn't, but it's close enough to achieving the same result that you will probably get away with it within acceptable limits. If you find it feels a bit out, try rotating it up to a half turn in either direction ( with the ocular set at zero, though if you're doing this part by eye, select your correct diopter ) and see if it's any better - Generally, it won't be. As I said, not quite the same process, but it should get pretty close. Otherwise you'll need to set up a jig for collimating it properly - and remember that MX11769's are a lot further out typically than MX10160's. David. Dude, you are talking about setting the diopter. You use a perfectly focused optical device to get perfect focus on the ocular to the image tube. This is zero diopter, after that is set, the diopter ring (with the single dot) is placed on the ocular cell and fastened with the retaining ring. See here: Section 3-13 http://nightvisionhome.com/wp-content/uploads/2014/04/PVS14-Training-Manual.pdf I can see how the terms might get confusing. The Diopter setting scope is referred to as "Collimator and Diopter Scope". Im having a hard time finding a link to the anvis manual that goes over collimating the unit. It is done by rotating the lens cell. Diopter is set by rotating the diopter adjustment ring. |
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As has been stated several times, collimation of bino's is done by turning the ocular lens to 'superimpose' both images on top of each other (as shown in the pictures above) It can be done on the Hoffmann ANV-126 or a TS-3895 with a bridge (what I use). Setting zero diopter is an entirely different procedure that is done prior to adjusting collimation. When a pair of bino's are properly collimated the images are 'parallel' to one another which significantly reduces eye strain.
The More You Know..... 
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As has been stated several times, collimation of bino's is done by turning the ocular lens to 'superimpose' both images on top of each other (as shown in the pictures above) It can be done on the Hoffmann ANV-126 or a TS-3895 with a bridge (what I use). Setting zero diopter is an entirely different procedure that is done prior to adjusting collimation. When a pair of bino's are properly collimated the images are 'parallel' to one another which significantly reduces eye strain. The More You Know..... Just out of interest, how long does the process of collimating and setting diopter for a bino take you in general? And an extra question, in case of a bino with articulating sides, is the collimation set with 64mm IPD (which I remember is the average) and then the rest of the arm positions are just close enough? With PVS-31 and PNVG I bet they use the best tubes that are within the acceptable range already. Though the PNVG is such a piece of oddness that I suppose it needs some fiddling around at manufacturing stage for each unit to align everything just right. |
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Quoted: Dude, you are talking about setting the diopter. You use a perfectly focused optical device to get perfect focus on the ocular to the image tube. This is zero diopter, after that is set, the diopter ring (with the single dot) is placed on the ocular cell and fastened with the retaining ring. See here: Section 3-13 http://nightvisionhome.com/wp-content/uploads/2014/04/PVS14-Training-Manual.pdf I can see how the terms might get confusing. The Diopter setting scope is referred to as "Collimator and Diopter Scope". Im having a hard time finding a link to the anvis manual that goes over collimating the unit. It is done by rotating the lens cell. Diopter is set by rotating the diopter adjustment ring. Quoted: Quoted: Quoted: Edit: and to give the correct answer, send them to someone who has the skills and the proper tools I think you are over-estimating the accuracy of the procedure - There is no prism inherent in the ANVIS ocular. Anyway, the simple version of the process for do-at-home is quite simple. This either works, or it doesn't. Get a large aperture camera with a good magnification and focus it on the stars, or at least at 100m to infinity - not any closer. Fix it somewhere if you can - with extra magnification if possible, and manual lens setting. Focus it, so that the lens stays fixed. Now use a big screen to view the video from it. Then with a well focussed monocular ( get it about as right as you can ) - looking at the same image, put the monocular in front of the camera with the diopter set to zero. Leaving the diopter at zero, rotate the lens assembly until it's in perfect focus - Note: The camera lens objective must have a fast lens and a reasonable aperture. OK, now you're done. Mark it with a marker pen, and an aligning mark on the housing. Finished ! Yes, I know this doesn't sound like collimating, and it isn't, but it's close enough to achieving the same result that you will probably get away with it within acceptable limits. If you find it feels a bit out, try rotating it up to a half turn in either direction ( with the ocular set at zero, though if you're doing this part by eye, select your correct diopter ) and see if it's any better - Generally, it won't be. As I said, not quite the same process, but it should get pretty close. Otherwise you'll need to set up a jig for collimating it properly - and remember that MX11769's are a lot further out typically than MX10160's. David. Dude, you are talking about setting the diopter. You use a perfectly focused optical device to get perfect focus on the ocular to the image tube. This is zero diopter, after that is set, the diopter ring (with the single dot) is placed on the ocular cell and fastened with the retaining ring. See here: Section 3-13 http://nightvisionhome.com/wp-content/uploads/2014/04/PVS14-Training-Manual.pdf I can see how the terms might get confusing. The Diopter setting scope is referred to as "Collimator and Diopter Scope". Im having a hard time finding a link to the anvis manual that goes over collimating the unit. It is done by rotating the lens cell. Diopter is set by rotating the diopter adjustment ring. I've highlighted the part you're looking for - You have to set the diopter first, and this can't be done by eye. It needs to be done by something with a fixed focus. After that, you can adjust the "collimation" by rotating no more than half a turn in either direction. Any further than that will not achieve what you're trying, and will put the diopter adjustment too far out. And I commented that this will *not* achieve collimation, but will achieve something close enough for most people. However since you have a camera setup still, you could just superimpose the left and right images on a computer to see where it is. Keep in mind, I was describing some basic do-at-home methods without the proper equipment - David. |
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I've highlighted the part you're looking for - You have to set the diopter first, and this can't be done by eye. It needs to be done by something with a fixed focus. After that, you can adjust the "collimation" by rotating no more than half a turn in either direction. Any further than that will not achieve what you're trying, and will put the diopter adjustment too far out. And I commented that this will *not* achieve collimation, but will achieve something close enough for most people. However since you have a camera setup still, you could just superimpose the left and right images on a computer to see where it is. Keep in mind, I was describing some basic do-at-home methods without the proper equipment - David. Quoted:
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Edit: and to give the correct answer, send them to someone who has the skills and the proper tools I think you are over-estimating the accuracy of the procedure - There is no prism inherent in the ANVIS ocular. Anyway, the simple version of the process for do-at-home is quite simple. This either works, or it doesn't. Get a large aperture camera with a good magnification and focus it on the stars, or at least at 100m to infinity - not any closer. Fix it somewhere if you can - with extra magnification if possible, and manual lens setting. Focus it, so that the lens stays fixed. Now use a big screen to view the video from it. Then with a well focussed monocular ( get it about as right as you can ) - looking at the same image, put the monocular in front of the camera with the diopter set to zero. Leaving the diopter at zero, rotate the lens assembly until it's in perfect focus - Note: The camera lens objective must have a fast lens and a reasonable aperture. OK, now you're done. Mark it with a marker pen, and an aligning mark on the housing. Finished ! Yes, I know this doesn't sound like collimating, and it isn't, but it's close enough to achieving the same result that you will probably get away with it within acceptable limits. If you find it feels a bit out, try rotating it up to a half turn in either direction ( with the ocular set at zero, though if you're doing this part by eye, select your correct diopter ) and see if it's any better - Generally, it won't be. As I said, not quite the same process, but it should get pretty close. Otherwise you'll need to set up a jig for collimating it properly - and remember that MX11769's are a lot further out typically than MX10160's. David. Dude, you are talking about setting the diopter. You use a perfectly focused optical device to get perfect focus on the ocular to the image tube. This is zero diopter, after that is set, the diopter ring (with the single dot) is placed on the ocular cell and fastened with the retaining ring. See here: Section 3-13 http://nightvisionhome.com/wp-content/uploads/2014/04/PVS14-Training-Manual.pdf I can see how the terms might get confusing. The Diopter setting scope is referred to as "Collimator and Diopter Scope". Im having a hard time finding a link to the anvis manual that goes over collimating the unit. It is done by rotating the lens cell. Diopter is set by rotating the diopter adjustment ring. I've highlighted the part you're looking for - You have to set the diopter first, and this can't be done by eye. It needs to be done by something with a fixed focus. After that, you can adjust the "collimation" by rotating no more than half a turn in either direction. Any further than that will not achieve what you're trying, and will put the diopter adjustment too far out. And I commented that this will *not* achieve collimation, but will achieve something close enough for most people. However since you have a camera setup still, you could just superimpose the left and right images on a computer to see where it is. Keep in mind, I was describing some basic do-at-home methods without the proper equipment - David. David, diopter is not set by rotating the lens cell. Diopter is set by rotating the diopter adjustment ring. Once that is set, the indicator mark snap ring is removed, relocated on the "0" and reinstalled. This is done after collimating the anvis. The anvis probably wont have a straight thru perfect collimation, but both images will be aligned on the same vector. |
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Quoted: David, diopter is not set by rotating the lens cell. Diopter is set by rotating the diopter adjustment ring. Once that is set, the indicator mark snap ring is removed, relocated on the "0" and reinstalled. This is done after collimating the anvis. The anvis probably wont have a straight thru perfect collimation, but both images will be aligned on the same vector. I think you're confusing the topic. I was not describing how to use the collimation bridge - I was talking about a simple process that can be followed at home to get the best possible DIY results without the correct equipment. For a couple of PVS-14's on a dual-bridge. The pitch of the ocular assembly is 32 tpi. The pitch of the diopter adjustment is 8 x 24 tpi. The ratio of the threads is less than 1 in 10. Turning the ocular assembly even a full half-turn after setting diopter correctly will only result in a diopter error of less than 0.5 diopters. 0.5 diopters is approximately 1 notch on the mark on the zero spot on the ocular - And that's assuming a full half-turn of the entire assembly - And likely it will be less than that even if that helps at all. Short of being able to twist the tube within the PVS-14, it's going to be pure luck if anyone achieves perfect horizontal or vertical alignment in the two images, so it's a best-effort approach and is a reasonable DIY way to set this up. The response I provided is about how to achieve best-as-possible collimation on a couple of PVS-14s on a dual-bridge. I realize you're trying to describe is how to collimate an AVS-6 here according to TM 11-5855-263-23&P - What you're saying is correct, but our posts are at crossed purposes here - I'm not trying to achieve that outcome and I'm also not trying to fix the inherent collimation failures of the AVS-6 NODs There may be better ways to collimate two PVS-14's on a bridge - and if you have any ideas, please share - Personally, I liked the earlier shim idea, which could theoretically make a difference and achieve a good outcome. For what it's worth, the first patented example of a PVS-14 dual bridge addressed this issue quite well - and they stated "At the present time, it is believed that there is no method of ensuring that any tWo monocular devices chosen at random Would be collimated." - This is still pretty much the case, and it's not really that different for ANVIS either - Sometimes there's just no easy solution to a problem - But there's still often an easy path to the best possible outcome - :) If you like, you can read their solution also - https://patents.google.com/patent/US6687053B1 Regards David |
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OK, I re-read what I wrote earlier and think I know where some of the confusion in what I said is coming from - Let me add the missing information to describe the "collimation" capabilities of the ANVIS lens. Then it might make more sense to everyone. The ANVIS lens cell is approximately 0.25mm off-axis - Literally, one side of the lens cell in a modern ANVIS lens is about 0.9mm thick and the other is 1.4mm thick - So as you rotate it a half-turn either direction, the actual glass optical axis swings about by 0.25mm out of alignment with the tube mechanical axis. You never really know where the perfect diopter setting is, or what the angle of the lens cell itself is, since there are three possible ways to assemble it, and I don't think any are consistently matched to the threads in the outer section. So this is why I said you can swing the lens around up to a half-turn in either direction after you set the diopter. This will shift the lenses around out of axis with the tube mechanical axis and mitigate, at least in one direction, the off-axis optical-to-mechanical alignment of the tube. But whether you can succeed in getting collimation with PVS-14's will depend significantly on how far off-axis a particular tube is. This process is also beneficial to setting up a single PVS-14, though I don't know of anyone who actually does this -but the camera method I described as above is suitable, and there's a slim chance that you can use the maximum offset of the lens to at least minimize the total system axis error. Regards David. edit: One error with the above, which I wrote without checking the figures - I think the actual pitch of the threads of the assembly are actually about 40 tpi - so the actual diopter error would be reduced by 30 percent. Would have been nice if they could have made it 32 tpi... Much less chance of cross-threading and damaging thread then- but the above ratio of how the collimation process affects diopter probably explains why they chose 40 tpi. |
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Quoted:
OK, I re-read what I wrote earlier and think I know where some of the confusion in what I said is coming from - Let me add the missing information to describe the "collimation" capabilities of the ANVIS lens. Then it might make more sense to everyone. The ANVIS lens cell is approximately 0.25mm off-axis - Literally, one side of the lens cell in a modern ANVIS lens is about 0.9mm thick and the other is 1.4mm thick - So as you rotate it a half-turn either direction, the actual glass optical axis swings about by 0.25mm out of alignment with the tube mechanical axis. You never really know where the perfect diopter setting is, or what the angle of the lens cell itself is, since there are three possible ways to assemble it, and I don't think any are consistently matched to the threads in the outer section. So this is why I said you can swing the lens around up to a half-turn in either direction after you set the diopter. This will shift the lenses around out of axis with the tube mechanical axis and mitigate, at least in one direction, the off-axis optical-to-mechanical alignment of the tube. But whether you can succeed in getting collimation with PVS-14's will depend significantly on how far off-axis a particular tube is. This process is also beneficial to setting up a single PVS-14, though I don't know of anyone who actually does this -but the camera method I described as above is suitable, and there's a slim chance that you can use the maximum offset of the lens to at least minimize the total system axis error. Regards David. Do I get this still wrong, or would you even with what you suggest still need to figure out the initial position of the offset lens? In the document you referenced it states to set the lens so that the image is centered vertically, but shifted right horizontally, so that when you combine any two monoculars that are "collimated" that way, and as the other is always upside down in that mount, they will be convergent and easy to look at. I am assuming they are talking about doing that with a test set. In what you write what I don't get is what good would it do to rotate a half-turn as you don't know the starting point, and without any measurements you are only hurting the diopter setting that you just did. |
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Quoted: Do I get this still wrong, or would you even with what you suggest still need to figure out the initial position of the offset lens? In the document you referenced it states to set the lens so that the image is centered vertically, but shifted right horizontally, so that when you combine any two monoculars that are "collimated" that way, and as the other is always upside down in that mount, they will be convergent and easy to look at. I am assuming they are talking about doing that with a test set. In what you write what I don't get is what good would it do to rotate a half-turn as you don't know the starting point, and without any measurements you are only hurting the diopter setting that you just did. Quoted: Quoted: OK, I re-read what I wrote earlier and think I know where some of the confusion in what I said is coming from - Let me add the missing information to describe the "collimation" capabilities of the ANVIS lens. Then it might make more sense to everyone. The ANVIS lens cell is approximately 0.25mm off-axis - Literally, one side of the lens cell in a modern ANVIS lens is about 0.9mm thick and the other is 1.4mm thick - So as you rotate it a half-turn either direction, the actual glass optical axis swings about by 0.25mm out of alignment with the tube mechanical axis. You never really know where the perfect diopter setting is, or what the angle of the lens cell itself is, since there are three possible ways to assemble it, and I don't think any are consistently matched to the threads in the outer section. So this is why I said you can swing the lens around up to a half-turn in either direction after you set the diopter. This will shift the lenses around out of axis with the tube mechanical axis and mitigate, at least in one direction, the off-axis optical-to-mechanical alignment of the tube. But whether you can succeed in getting collimation with PVS-14's will depend significantly on how far off-axis a particular tube is. This process is also beneficial to setting up a single PVS-14, though I don't know of anyone who actually does this -but the camera method I described as above is suitable, and there's a slim chance that you can use the maximum offset of the lens to at least minimize the total system axis error. Regards David. Do I get this still wrong, or would you even with what you suggest still need to figure out the initial position of the offset lens? In the document you referenced it states to set the lens so that the image is centered vertically, but shifted right horizontally, so that when you combine any two monoculars that are "collimated" that way, and as the other is always upside down in that mount, they will be convergent and easy to look at. I am assuming they are talking about doing that with a test set. In what you write what I don't get is what good would it do to rotate a half-turn as you don't know the starting point, and without any measurements you are only hurting the diopter setting that you just did. Up to a half-turn. The key thought here is that you don't know where the offset it - So you want to rotate it left and right of perfect focus by up to a half turn. Somewhere along this process, you should theoretically bring the images into the same plane - It might be without rotating the assembly. It might be 1/8 turn clockwise, or 1/2 turn counterclockwise. With a collimation bridge, you can see the results as you move things, so you know in real time if it's getting better or worse. Otherwise, it's going to be tough - but it is still possible with just cameras and POI checks and stuff. There may be two possible solutions ( actually, up to four are possible ) - and one of them will be the best too, but I wouldn't recommend going that far without proper equipment. Yes, you are hurting the diopter settings, but only by up to 0.5 diopter as I mentioned. That's the limit of the diopter zeroing anyway. Hmmm. I wonder if you can modify an old PVS-7 without a tube and turn it into a collimation bridge? Regards David |
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Quoted:
Up to a half-turn. The key thought here is that you don't know where the offset it - So you want to rotate it left and right of perfect focus by up to a half turn. Somewhere along this process, you should theoretically bring the images into the same plane - It might be without rotating the assembly. It might be 1/8 turn clockwise, or 1/2 turn counterclockwise. With a collimation bridge, you can see the results as you move things, so you know in real time if it's getting better or worse. Otherwise, it's going to be tough - but it is still possible with just cameras and POI checks and stuff. There may be two possible solutions ( actually, up to four are possible ) - and one of them will be the best too, but I wouldn't recommend going that far without proper equipment. Yes, you are hurting the diopter settings, but only by up to 0.5 diopter as I mentioned. That's the limit of the diopter zeroing anyway. Hmmm. I wonder if you can modify an old PVS-7 without a tube and turn it into a collimation bridge? Regards David Alright, thanks for the clarification. Now we are on the same page. The PVS-7 thing came to mind too, would be probably the cheapest way to do this right, assuming it's as doable as it first sounds in my head. |
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Quoted: A pvs7 flipped backwards sounds like a great idea, but are there optical inaccuracies in the mirrors that go to the eyepieces that could still have error? That just means you baseline that aspect before any others. Collimate the PVS-7 then collimate the binocular system... I have no idea if it would work - but it sounds plausible without having actually tried it - David. |
| Is it possible to collimate a PVS-14 so that it could be used in front of a day scope? I'm guessing the housing would have to be modified so the tube could be tilted slightly? Obviously a clip on would be 10x better but, it would be kinda cool if you could for a "plan B" option. |
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Quoted: Is it possible to collimate a PVS-14 so that it could be used in front of a day scope? I'm guessing the housing would have to be modified so the tube could be tilted slightly? Obviously a clip on would be 10x better but, it would be kinda cool if you could for a "plan B" option. It is possible to create a boresighted PVS-14. There are actually significant tactical reasons to do this aside from just an emergency "clip on" and it has to do with instinctive shooting and CQB. It's one of the reasons that a PVS-22 allows a measurable performance increase for the operator over ANVIS monoculars that has nothing to do with it's visible-passthrough. And while the methodology is fairly trivial, it's not something that should be attempted without the capability to make your own PVS-14 upper. Otherwise you might as well make a boresighted monocular from scratch. It's also considered to be a controlled technology at this point, so the specifics can't be openly posted here. Tilting the tube would do it, but would cause focus issues unless you could tilt it around the petzval radius, and even then you're going to mess up your infinity focus. The use of risely prisms attached to the ocular would work also, and might be possible as a DIY experiment. You want a pair of prisms with a maximum diopter of around 2.0 though, which might be difficult to find cheaply - I know a few people who tried to do that, but I don't know of any who succeeded. Regards David. |
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Now thinking about what Nivisys wrote after I asked for help with MUM bino collimation, it's odd their bridge is not one where the other monocular is flipped 180 deg relative to the other. They said to, and checked what can be told to me as a foreigner, collimate any binos they sell and mark the monoculars as side A and B. That sounds like a pain for maintenance compared to the method David referenced where every monocular that goes out is adjusted so that the image is center vertically, but shifted right (assuming the correct monocular position).
Now their new bridge is even more odd, it has a rotation of 90 degrees between the monoculars. Perhaps it looks cool, but doesn't make things easier at all. Almost every other MUM bridge has 180 deg rotation difference between the monos. Not that anyone but Nivisys would collimate their MUM binos I guess.. Shimming the tubes is a tedious task compared to rotating the lenses on a tester. Selecting paired tubes on the other hand is easier and I doubt they do much shimming if not absolutely necessary. |
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i have dual mums and never needed to colimate them - i asumed that the lenses were set dead level in their housings and must not need it - maybe i was just lucky
i also have dual gt14 and had to sdjust those to get a decent colimated image but the eyecups can be rotated on those then tightned so it was no bother to do it. i just use the binocular type adaptor and it works real well i find |
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Quoted:
i have dual mums and never needed to colimate them - i asumed that the lenses were set dead level in their housings and must not need it - maybe i was just lucky i also have dual gt14 and had to sdjust those to get a decent colimated image but the eyecups can be rotated on those then tightned so it was no bother to do it. i just use the binocular type adaptor and it works real well i find I had slight eyestrain with that particular bino setup and my best guess was it came from collimation error, but could have been something else. The other tube had a shift in the image that was much worse than in the other tube. Holding them manually in front of my eyes in certain positions (rotated differently) got it better, but obviously I could not try that for longer periods. How I noticed the differences is I relaxed my eyes and rotated the monoculars and could see stars rotating. Takes a little effort to keep your brains from merging the image, but just staying relaxed stops that from happening. Can the GT14 eyepieces be collimated like Anvis? Edit: wish the GT14 optics were Anvis compatible, I love the slightly larger FOV (45 perhaps?). And as you said they have updated them to get rid of the distortion, that sounds very good. Edit number 2 and a bit offtopic, you can hit me with IM if you would like: do you have an image of the version of GT14 you are running, are the optics different externally? As I google GT14 I see there is a version with different looking optics than what is shown at NVision Optics website. |
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i find i can colimate the gt14 by first setting the diopter then as the whole eyepiece pulls on and off - it can be rotated as needed then pushed back on at the right place
(then the lock ring tightened )the gt14 's are just a little heavy when headmounted but nice as a handheld bino |
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