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vlaiv

NV eyepieces - a new potential equipment segment?

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Due to recent participation in discussions on status of NV, I had opportunity to get to know a bit better what principle of operation NV devices utilize.

Current state of affairs is to use ready made NV device and use eyepiece. It is form of EP projection approach because NV devices are made to be used stand alone - much like consumer type point and shoot camera, it has integrated lens.

I deliberately used above comparison, because I needed a mental image of how NV devices work in terms of optics, and it is analog to using EP projection technique with point and shoot camera (or smartphone camera).

Diagram on wiki explains this very well:

image.png.b8dd92487dd3f7d29dc44bc1e5da40eb.png

Device needs collimated beam on "input" because it has integrated focusing lens. Next stage is photoelectric device turning photons into electrons. These electrons hit electron multiplication device that sends stream of electrons hitting phosphorous screen that emits light. Light is then sent thru number of lenses that represent another "scope - ep" combination.

What I'm wondering is if above device could be turned into simple eyepiece. Or maybe EP created using same principle as above. This could potentially bring down cost of EV equipment and with utilization of astro standards (like 1.25" / 2" barrel) - ease of use as well.

Focusing lens at the front is not needed, because light beam from scope is already focused. This would also imply that eyepiece is not needed in front of EV eyepiece of such design.

Does anyone have idea what is the size of photoelectric device used at front? That would need to be matched fully illuminated field of scope for best utilization - it's a bit like size of field stop with regular EP.

There is also matter of "resolution" of the image, that needs to be matched with the eye angular resolution. Electron multiplication device actually works as if it has "pixels", here is diagram from wiki:

image.png.f249e482d05b6a1368c4e2a342bdce4e.png

This type of electron multiplier is used in Gen II and Gen III devices. Holes are 8um in size, but spaced at 10um. This effectively defines "pixel QE" and sampling resolution of EV device, when coupled with certain scope.

Any ideas on this topic?

 

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Thanks for posting. The diagram seems to sum things up nicely.

I’d be surprised if the nice people at Daystar aren’t having a look at this.

Paul

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25 minutes ago, Paul73 said:

Thanks for posting. The diagram seems to sum things up nicely.

I’d be surprised if the nice people at Daystar aren’t having a look at this.

Paul

Absolutely, to be honest I think we are going to see a few manufacturers taking the initiative on this.  I mean think about it,  this is exactly how you open up your market  - now  the view at the eyepiece looks remotely like the picture on the box.  problem though is the high cost and the tech restrictions placed on the technology by the USA.   My bet is that within 10 years we will be seeing a commercial offering aimed specifically at the astro market. 

Jim 

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I see couple of "problems" that need to be addressed first with above approach.

1) Should it be eyepiece, or more flexible device like a "filter". Now that @Paul73 mentioned Daystar - much like a Quark / Quark combo. Problem that I'm seeing with this is that phosphorous screen is going to be very "spherical" light source, so not sure if regular eyepieces will be able to cope with that - we all know that EPs have trouble handling fast optics.  On the other hand, having integrated EP optics at EP end would reduce flexibility of such device.

2) This is in essence analogue device, I'm wondering what would be QE of such device - given photoelectric element and of course electron multiplier. If we look at above diagram for one type of electron multiplier with holes - they seem to be rather sparse and overall "QE" can't be that high. I also wonder about "read noise" of such device, or rather electron multiplier thermal noise. Is it comparable to modern CMOS sensors?

If we replace photoelectric element with CMOS sensor, and phosphorous screen with some other type of monochromatic screen that gives off light in green spectrum, and electron multiplier with electronic processing unit that scans CMOS sensors and produces output on screen - would it still be the same device? In principle it would. Maybe even more sensitive than NV. Probably bulkier? I wonder if there are screens with pixels small enough to produce natural image after "EP amplification" - I guess we can calculate this from human angular resolution and apparent field of view.

Let's say we have something like 60 degrees AFOV, and human angular sensitivity is about 1'. That means that we need at least 3600 pixels across diagonal for image to look natural. Putting that in one inch field gives 3600ppi display - not sure such things exist at the moment.

 

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I am going to say one thing that many will not like but I think that time will give me the reason

The traditional astrophotography will be reduced to a small group of selected practitioners while the EAA or NV will attract many other people interested in seeing what's up there.

Electronics is the future

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1 hour ago, elpajare said:

I am going to say one thing that many will not like but I think that time will give me the reason

The traditional astrophotography will be reduced to a small group of selected practitioners while the EAA or NV will attract many other people interested in seeing what's up there.

Electronics is the future

I think that you are quite right in growing EAA/NV potential. I'm not sure that AP practitioner base will shrink, people do get hooked to it, but given the cost and involvement, over time, many people wanting to start "taking pictures" of night sky will turn to EAA (live stacking) rather than full fledged AP.

Both NV and Live stacking need simplification / cost reduction and user friendliness to move forward at speed. At the moment I think NV is hampered both by high price and also availability and legislative. Some countries prohibit use of these devices, because they are often associated with firearms - either in military or hunting role.

Dedicated astro NV device would certainly be exempt from such laws?

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Just had my first NV moment :D

Researching further, it's safe to say that CMOS + AMOLED technology is not there yet. Display side of things is lacking - it turns out that smart watch market is interesting one for small round displays and many are available today, but unfortunately resolution offered is too small.

Most displays can be classified as 300-400dpi displays. Even highest resolution displays nowadays are still below 1000dpi, let alone 3600dpi needed.

To test what would image be like with current displays - I took 32mm eyepiece, unscrewed the bottom and put it against smartphone display. I even loaded M51 mono image I took some time ago to have proper "feel" of it. It indeed works, image can be seen in sharp focus, but pixels are obvious. I remember someone using this technique to judge EP quality - actual pixels can be observed when EP is used against the display.

It does however feel quite "real" in terms of observing. Given proper resolution, I would be really happy with such NV eyepiece - consisting of CMOS and proper AMOLED or similar display.

Back on the original topic, @alanjgreen brought to my attention that it has been covered before, and indeed, this post is rather informative:

It seems that Image Intensifier Tubes can be used as starting point for constructing true astronomical NV eyepiece / filter. These are "hearts" of NV devices currently used. I wonder if such items could be purchased in retail, and what would the price be. Manufacturer mentioned for EU market, indeed has these listed on their website, but currently only military application is envisioned and no retail of these is done.

For phosphorous screens, adequate resolution is listed at 64lp/mm, which translates to ~3200dpi, so above calculation is quite good - we need at least 3000dpi displays to be able to project natural looking image.

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6 minutes ago, Thalestris24 said:

The Photonis image intensifiers cost 000's :(

Louise

One of the reasons for this thread - could we find affordable gear to bring NV to masses?

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18 minutes ago, vlaiv said:

One of the reasons for this thread - could we find affordable gear to bring NV to masses?

I guess they aren't mass market devices so prices are likely to remain high. I also suspect the devices will only work well in fairly dark skies? So probably no use for lots of people like me who live in cities and have high skyglow.

Louise

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Well, there is potential use even in LP.

These devices have quite a broad spectral response, up to 1000nm wavelengths. They "convert" all wavelengths in one particular - green display, or "broadband" type - white light. But this means that you can observe Ha/Hb/OIII/SII emission nebulae without restriction. You can use new multi pass NB filters - like duoband or triband, without worrying of human eye sensitivity in particular range - it "converts" all those wavelengths in part of the spectrum where our eyes are the most sensitive.

For stellar/galaxy type targets, you can use NIR part of the spectrum with usage of NIR filters, otherwise only used for imaging, since eye can't detect wavelengths above 700nm on its own.

Targets that will probably see the least benefit in LP would be reflection type nebulae. This agrees with recent Stu's report on using NV gear.

But those price you found are seriously steep.

I managed to find couple of sources of Image Intensifier Tubes via alibaba - a few Russian manufacturers, but again no prices were given. These are earlier generation devices - like Gen 2+ or Gen 3, but have good specs (~60lp/mm, SNR of about 20) and larger diameter like 37.5mm or even larger models - which is good for astronomy usage compared to standard 16 and 18mm, but again no prices listed and aimed at military usage.

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26 minutes ago, vlaiv said:

Well, there is potential use even in LP.

These devices have quite a broad spectral response, up to 1000nm wavelengths. They "convert" all wavelengths in one particular - green display, or "broadband" type - white light. But this means that you can observe Ha/Hb/OIII/SII emission nebulae without restriction. You can use new multi pass NB filters - like duoband or triband, without worrying of human eye sensitivity in particular range - it "converts" all those wavelengths in part of the spectrum where our eyes are the most sensitive.

For stellar/galaxy type targets, you can use NIR part of the spectrum with usage of NIR filters, otherwise only used for imaging, since eye can't detect wavelengths above 700nm on its own.

Targets that will probably see the least benefit in LP would be reflection type nebulae. This agrees with recent Stu's report on using NV gear.

But those price you found are seriously steep.

I managed to find couple of sources of Image Intensifier Tubes via alibaba - a few Russian manufacturers, but again no prices were given. These are earlier generation devices - like Gen 2+ or Gen 3, but have good specs (~60lp/mm, SNR of about 20) and larger diameter like 37.5mm or even larger models - which is good for astronomy usage compared to standard 16 and 18mm, but again no prices listed and aimed at military usage.

Yeah, I've no doubt there are cheaper ones available but they will still be relatively expensive. I've done some imaging in near IR and it cuts out lp completely but only stars were visible so interesting but rather underwhelming. I'll stick to live luminance stacking which I find quite enjoyable, even though it doesn't result in works of art :)

Louise

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10 hours ago, Thalestris24 said:

I guess they aren't mass market devices so prices are likely to remain high. I also suspect the devices will only work well in fairly dark skies? So probably no use for lots of people like me who live in cities and have high skyglow.

Louise

There is plenty of info on the forum about these devices now Louise, but yes they are very expensive. With heavy filtering in Ha they will, however, show some of the very faint objects even under light polluted conditions.

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2 hours ago, Stu said:

There is plenty of info on the forum about these devices now Louise, but yes they are very expensive. With heavy filtering in Ha they will, however, show some of the very faint objects even under light polluted conditions.

I still have problems imaging in Ha here using a 3.5nm filter :( I think, even in narrowband, the lp combines with poor transparency to make my astro life a misery!

Louise

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Posted (edited)

It surprises me that no one jumped in to comment that the use of NV monoculars afocally is a restriction the pvs-14 has because of how far inset the input window of the Intensifier is on the pvs-14 housing. Being that far inset makes it all but impossible to focus at infinity. Also no readily available c-mount adapters to put on to allow c-mount nosepieces or different lenses to use.

 

The use of NV devices as Prime Focus eyepieces has been going on for a long time though. The ocular of most Night Vision devices is right around 27mm, so using Prime Focus you calculate magnification based on a 27mm focal length eyepiece in whatever focal length scope you have. Most Prime Focus users of Night Vision are simply using standard focal reducers to get brighter images that lessen scintillation. The same focal reduction can be done afocally by using a longer focal length eyepiece than the ocular of the night vision device (27mm) - 56mm plossl is what I use afocally to get reduction to .5x or if I’m using the device in Prime Focus, I use a .5x focal reducer. The issue with Prime Focus and reducers is usually that the back focus requirements to place a focal reducer before a diagonal and then put an eyepiece in the diagonal and still be able to come to infinity Focus is near impossible in most scopes unless you start cutting tubes to get the required back focus needed.

 

using a focal reducer is not required though. Native focal lengths of F/12 can even be used with longpass filters for cutting light pollution. It’s only using narrowband that scintillation gets too noisy when photon starvation happens with longer focal lengths. The cure to get smooth images again is to reduce the FR and if you have manual gain adjustment, turn down gain a hair to balance brightness with smoother image from less scintillation. 

The workaround for Night Vision eyepieces at Prime Focus is to place the focal reducer on the nosepiece of the night vision device. You simply place the Monocular with nosepiece and focal reducer screwed on nosepiece, right in a diagonal or in the case of Prime Focus with a reflector, just directly in the focuser.  In that configuration, it will not give a true .5x reduction, but still gives a substantial enough reduction to take an F/5 native focal ratio down somewhere between F/3 and F/3.2 (I need to drift time to find exact reduction still but usually it’s sufficient enough to not bother with the technicalities of drift timing). Reflector use is tricky with focal reducers as it usually requires an adjustable secondary placement so a truss tube dob could shorten the distance between primary and secondary to get required back focus to use the reducer on the nosepiece. Luckily for newt owners, dobs are available in fast focal ratios already and a coma corrector can still work to get a nice flat field. Some newts are optimized. Astrographs that are native F/4 but come with reducer to work at F/2.8 work really well with Prime Focus Night Vision eyepieces.

 

The other issue being that monoculars with housings made to place the Intensifier input window close enough to input objective lens opening, usually are either fitted with a c-mount adapter or have a c-mount adapter built in. Many devices have these c-mount adapters built right into the housing. The issue is that using a 1.25” focal reducer will vignette quite noticeably so most go for more expensive 2” reducers in .5x, .7x, .75x or whatever flavor of reduction that works best with the telescope. I use .5x all the time if reducing. These regular type focal reducers can also be used in combination with afocal use to further reduce the overall focal ratio. For instance - afocal pvs-14 use on an SCT at native F/10 attached to 55mm plossl gives a .5x reduction bringing to the SCT to F/5. Now attach another focal reducer of say .7x to the end of the 55mm plossl - reduction is now brought down even further to F/3.3 (as Gavster uses)

 

In the UK and Canada, availability of housings different than the pvs-14 is scarce. Kite makes some suitable biocular goggles I’ve seen used on eBay.uk, but the c-mount adapter would have to be custom made. Starlight NV has a housing with built in c-mount for the older and very heavy EEV p8079hp gen 1 cascade tube (also called an ABC Tube) which is the only gen 1 Intensifier that is powerful enough to use with narrowband Ha filtering. It is basically three gen 1 tubes fiber optically coupled to each other so each stage feeds the next. Gain is around 100,000x. Suitable for narrowband Ha but the resolution is lower than gen 3 tubes. It has a resolution of 40 lp/mm on a 40mm input window. It also has some noticeable fisheye effect around the edges. A housing could also be custom made for that tube, but making a decent housing for the gen 3 Harder Digital or Photonis tubes available in the UK might pose some optical challenges to get it just right. The turnkey solution is to just buy a pvs-14 and use it afocally either with the adapter that TNVC makes to couple to dioptrx threads on Televue eyepieces or as I have done, buy a digiscoping adapter and clamp the adapter to the 55mm or 56mm plossl (I use the Meade 56mm plossl) and use the 1/4-20 hole of the night Vision Monocular to attach to the digiscoping adapter. I use a Baader adapter that allows easy placement of the night Vision Monocular 1x objective lens right over the field lens of the plossl. Novagrade also makes some slip fit type adapters that would work for afocal use.

 

After reading up on the formula to get reduction in FR from using an eyepiece in longer focal length than the native 27mm ocular of the Night Vision device and seeing results that Gavster posted, I’m now mixing it up with some Prime Focus NV and some afocal NV. Both methods get excellent results.

 

there are also some doing direct NV imaging by using a camera attached by relay lens to a Night Vision device. N that case the ocular of the night vision device is unscrewed and a relay lens (either ccd or dslr relay) put in its place and attach a camera to the relay. Single shot narrowband Ha pictures can be done with low exposure time fairly easily if you have tracking. I use manual mounts only, no tracking, and have still taken interesting sub 1 Second exposure pictures of Horsehead, Cats Paw, Lagoon, Triffid, Omega, Orion, Rosette, etc. 

unfortunately with no tracking though, they do not come out anywhere as close even to the phone camera shots seen by members. It’s kind of fun though. I have both ccd and dslr relays, but only tried with a dslr so far.

I bought all my NV devices used or refurbished and some I’ve upgraded to newer high spec tubes a few years later after using them as is for awhile. I’m in USA though, so more readily available used devices. I did save some money vs new but you kind of have to be familiar with the types of devices and scour eBay or classifieds constantly. It takes a lot more research it seems to get what you need used vs just buying a turnkey solution new.

One day I might get a tracking mount, but since I really love the simplicity of manual mount and just popping a night Vision eyepiece in or an afocal stacked NV device and just go, it isn’t a priority for me.

Edited by Vondragonnoggin

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Posted (edited)

Interesting discussion for sure. This site is really laid out pretty nice and easy to navigate. I’ve lurked here awhile but now this will be my third post. I love discussion on NV use and equipment though. So few using it that sometimes it’s difficult to get discussions going on it with large participation. 

 

I guess I should mention that I’m using NV with a couple refractors (72mm, 120mm, and 150mm)  and a 150mm mak and some slr lenses. My back not so good so the smaller scopes suit me well. Would be fun to have a big scope to use with it, but just can’t do it anymore.

 

A lot of good information here already and some long time users too. PeterW helped steer me on some purchases and gave solid information when I started with it beginning of 2014. Gavster’s afocal use prompted me to try afocal again too. I had tried it with a zoom, but all focal lengths on the zoom were shorter than the ocular on the device so I was increasing focal ratio. Great stuff.

Edited by Vondragonnoggin
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Posted (edited)
On 29/03/2019 at 04:50, saac said:

Absolutely, to be honest I think we are going to see a few manufacturers taking the initiative on this.  I mean think about it,  this is exactly how you open up your market  - now  the view at the eyepiece looks remotely like the picture on the box.  problem though is the high cost and the tech restrictions placed on the technology by the USA.   My bet is that within 10 years we will be seeing a commercial offering aimed specifically at the astro market. 

Jim 

There were previously two commercial offering’s aimed at the Astro community in the US. One offered a device called the Collins I3 eyepiece and actually was partnered with Televue to make its oculars in 15mm and 25mm focal lengths. The other product was a product called the Binocular Photon Machine. BiPH for short which used an 18mm size thin film  gen 3 GaAs Intensifier in a housing that coupled a Russian designed panoramic biocular.

They both had the green phosphor thin filmed Gen 3 Gallium Arsenide (GaAs) photocathodes and actually were hand picked with high specs geared for astronomy

They both went out of production. Doug Baum of the BiPH offering still supports his product for owners which is nice. 

 

http://www.ceoptics.com/ - Collins website

 

http://www.nightvisionastronomy.com/ - BiPH

 

Neither has been in production over 5 years now. 

 

 

Edited by Vondragonnoggin
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Posted (edited)
2 hours ago, Vondragonnoggin said:

There were previously two commercial offering’s aimed at the Astro community in the US. One offered a device called the Collins I3 eyepiece and actually was partnered with Televue to make its oculars in 15mm and 25mm focal lengths. The other product was a product called the Binocular Photon Machine. BiPH for short which used an 18mm size thin film  gen 3 GaAs Intensifier in a housing that coupled a Russian designed panoramic biocular.

 

Thanks for that Vondragonnoggin.   I think if we are going to see NV be a commercial success in the astro market then we need to watch what happens in the USA first , that's where it will happen.  I think it's just waiting for that breakthrough moment where there is enough uptake to drive the retail price down.  We needs lots of enthusiastic early adopters.  

I love that tag line on the Collins website "Messier would have owned one"    brilliant  and true .

 

Jim 

Edited by saac
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Might take the next breakthrough tech in military use and having that cause adoption of the new tech in military and consequential abandonment of current night vision tech. The market would be flooded with surplus and used devices/intensifiers. More importantly, if Night Vision wasn’t the current state of the art nighttime surveillance tech, then maybe ITAR would change some restrictions on import/export.

I know some would be scrambling to try whatever new tech had caused that, but the older would remain a viable observing tool that lasted a lifetime. Tubes generally are good for about 10,000 hours with a drop in performance in the latter few thousand hours, but not a drop enough to make them unusable.

10,000 hours use for most people would equate to a lifetime of observing hours. I have some devices with older tubes that are still as great as when I first tried them. I also have some devices where I upgraded tubes for some performance gains' but any of them from older thick film tubes with 21 S/N still work for me. You don’t need the absolute highest spec to enjoy them. It is nice if you can afford it and it’s offered in your area. The difference I’ve seen in tube performance is not a matter of see it or don’t see it most of the time. Threshold objects for sure benefit from higher spec tubes, but you don’t always look at threshold objects.

 

I have all green phosphor systems and sometimes surface brightness is low enough on threshold objects to completely make green tint disappear and just appear black and white. I’ve also been able to use averted vision techniques on objects with Night Vision eyepieces. I’m using small scopes though. Those threshold objects would appear less subtlety if I got bigger scopes but still retained fast focal ratio and drove to dark skies.

 

I could also keep using the same scopes but get a tracking mount and play with exposure time on my camera to make a few details come out that were more difficult just visually observing. Resolution is not as good as modern cameras but it’s still nothing to sneeze at so to speak. 64 lp/mm over an 18mm window is fairly high resolution and a camera would pick it up better than the human eye distinguishing subtle brightness changes over the phosphor screen.

Hopefully something will happen to make them more available to a larger number of countries at lower cost.

Used market in the US has been good enough to find gen 3 monoculars that are narrowband Ha capable as low as $700

The highest spec, best performance devices still cost $4000 - $5000 over here though and comparatively some $6000 - $8000 or more in the UK. That’s going to be prohibitive for too many people. FOM of 1350 is about the lowest I’d recommend for narrowband Ha work. New tubes getting average FOM’s of 2200-2500 now though and some super tubes have around 2800, so 1350 still very low comparatively, but if you could get it for $700-$1250 it would be more attractive for a lot more people. As long as halo and EBI specs stayed relatively low (< 2 on EBI and less than 1.5 on halo) then using with some narrowband filtration still would bring out a number of difficult nebulae. EBI specs can change drastically with temperature too. A modded device using a cold finger might provide better signal over background noise than a high spec tube in really warm weather. As far as I know, no one has done this yet. Maybe because it might decrease performance being too cold. I don’t know specifically if extreme cold would affect the tube performance negatively.

EBI spec - This is the amount of light you see through a night vision device when an image tube is turned on but no light is on the photocathode. EBI is affected by temperature; the warmer the night vision device, the brighter the background illumination. EBI is measured in lumens per square centimeter (lm/cm2). The lower the value the better. The EBI level determines the lowest light level at which an image can be detected. Below this light level, objects will be masked by the EBI.

Getting good performance tubes makes the viewing more pleasing though with less scintillation and for devices with manual gain, highest performance tubes keeps the signal strong while turning down the gain a little to lessen scintillation. You can still do this with tubes in the FOM of 1350 range though.

It’s like any other equipment in the amateur astronomy gear offerings. Some will have to get the best and some will settle for less than the best. I’ve always been a “not the best” being ok for me as I can ignore a lot of things that bother the more discerning viewer. I’m ok with a little more balancing of cost to performance ratio. Picking a filter width can make a huge difference in S/N on Ha coming through also. Going to narrower notch can really increase the contrast at the expense of more scintillation, so for my older tubes with lower S/N, I just put up with more scintillation. All my gen 3’s have at least 64 lp/mm spec and some have 72 lp/mm, even down to my Omni IV era tubes (the Omnibus contract having a certain stated minimum spec standard promised for contract purpose).

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Thought I would post another example of a conversion for an NV eyepiece. The PVS-4 Starlight scope has adapters available that can be used once the large 4x power Mangin mirror catadioptric lens is removed. This was originally a gulf war era gen 2 device, but later models were gen 3 and Gen 3 tubes for them are very desirable, but a bit rare. The tubes though, are 25mm optical window tubes and still have resolution of 64 lp/mm. Spread out over 25mm it is pretty good resolution. The added size of the 25mm Tube is considerable. The penalty is heavier weight, bulkier housing. The benefit though is 65° AFOV. There is a biocular available for them as well that is 4” across allowing the use of both eyes at a comfortable distance from the 4” ocular lens. This biocular lens is rather heavy and adds to the already higher weight of the larger housing. I’ve never had the tube tested specifically but there are minimum Omnibus contract specs which are pretty decent and the gen 3 tube is very capable of narrowband Ha to 3nm even. It is a variable gain device so the option to turn down the gain a hair to reduce scintillation is there. I use this feature all the time. Here is mine with the biocular fitted and a 2” nosepiece to put in the diagonal of my scopes. Works just like a Prime Focus 18mm device, just much larger. In comparison to show size I have a 28mm RKE 1.25” eyepiece and a large can of beef ravioli (no longer have the ravioli ;) ).   While these still are not exportable, I could imagine that Photonis might have some older tube with a 40-50mm optical window that could be converted to an eyepiece if you have a scope and focuser to handle the weight. It’s also possible that we may not be seeing tubes they have made for machine vision imaging that rival in size but never seen in a wearable Monocular or goggle because of the size being impractical. One of these days I need to call Photonis again and ask if they have any intensifiers with equivalent of 4G or XR5 performance but with larger optical windows. Tank periscope sights would be an application that would require a larger FOV and larger Intensifier. Could be an interesting phone call.

 

6F8246F8-D0E2-47DC-A602-D4D40B8487BC_zps

 

 

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The Monocular configuration of this is also very good. Still a 27mm focal length, but a very large field lens and very good optics.

 

C446ECD6-6418-4CCC-B225-44F9CE026EB0_zps

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Paired with a camera these Photonis XX1332 gen 2 tubes might be cool for an EEVA setup

 

https://www.abex.co.uk/esales/optical/philips/image-intensifier/xx1332/0e543_8027_a/index.php

 

this site has info on meteor imaging and some suggestions on what works well and includes ccd’s paired with the xx1332 Intensifier 

https://www.imo.net/resources/metrec/

Im guessing here though, that Photonis which took over Philips awhile back, May have some large intensifiers with newer tech available in the UK that could be converted to an eyepiece or intensified camera setup with a live view screen.

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