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Vondragonnoggin

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About Vondragonnoggin

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    Computers, Music Gear and making Music, Night Vision, Astronomy, Astronimy Gear, Photography, Video Gaming
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  1. I put a 10” polymer grab handle on my iOptron mak 150. Much easier to carry and mount
  2. 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.
  3. The Monocular configuration of this is also very good. Still a 27mm focal length, but a very large field lens and very good optics.
  4. 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.
  5. 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).
  6. 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.
  7. 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.
  8. 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.
  9. I just read through the whole thread here and wanted to sign up to give my own take on NV astronomy. Been posting about NV Astronomy for a few years now over on CN. Since the days when it was still just the Video Astronomy forum all before the EAA letters came into it and it was a sub forum of Equipment discussions. Davy a few posts up was kind enough to create a whole section on VAF for me to fill up with information on NV Astronomy. I’ve invited folks over a bunch of times but it remains pretty stagnant since 2015 when I filled up a bunch of threads with info. Davy and Ken and the rest of the guys there are more than welcoming though, so I continue discussions on scopes and observing and all that. The EAA section at CN used to be real friendly to us NV Astronimers too, but lately learned some have left because they are tired of “NV” posts. Regular observing forums have gotten more friendly and admins have no issues with posts in Deep Sky, but some members still do as well as trying to suggest NV as an option in Beginners forum being still frowned upon over traditional “get a big reflector” advice or if you are going to be viewing in red/white zones you’ll see “get to dark skies or be limited to planetary, some globs and open clusters, and lunar and only the very brightest nebula”. I'm in red/white zone (Bortle 7) and particularly lazy so NV was my choice to see more without having to pack up stuff and drive to dark skies. I don’t know what the solution is overall, but can tell you that having dedicated sections on sites with less traffic won’t get much attention to posting or attracting members or more importantly, changing minds about NV being a valid observation tool. I think CN is saturated enough to get its own forum, particularly if we are making the camera EAA guys up and leave, but on the whole and particularly after a concerted effort to organize “Best of NV” threads to make them easy to find, I would hope it went back to camera and NV EAA users coexisting peacefully and joining each other’s discussions. I jump in camera EAA discussions still and used to more because I just picked up the process being used by reading the threads and getting familiar with some of the tech. We are all just trying to see more in various ways whether live with NV or near real-time with a camera. I still use my regular eyepieces frequently too. I like planetary still and NV is no good on bright objects like lunar and planetary. what I’ve seen though, and it’s natural to want to do this, is that members that just grab on to EAA camera or EAA NV, get pretty excited about seeing things they never thought possible previously without getting huge telescopes or requiring the darkest skies and they want to “shout it from the rooftops” to others or be able to suggest it as an alternative to “get a bigger scope and drive to darker skies” and traditional method astronomy practitioners see it as “bragging”. It doesn’t matter if the same behavior happens when they themselves upgrade to larger scopes or dominate the Deep Sky forums because they have giant dobs. That of course is not “bragging”. It’s a double standard that persists to this day on most forums. I don’t know how to solve it, but I rarely post in Deep Sky anymore. I stick to EAA forum or sites like VAF where it wouldn’t matter because we call everything Video Astronomy over there pretty much, even if the term doesn’t specifically fit the tech. I continue to make small mentions of NV equipment where I deem it appropriate and not dominating my suggestions. I mix it up with traditional equipment suggestions and NV suggestions and (because I chose to participate in camera EAA threads so much) some camera EAA suggestions. If someone has a tracking scope and limited budget that falls short of the more expensive NV offerings, I suggest EAA with a camera. I don’t even use tracking mounts myself but I know that that is a pretty easy switch for a lot of folks that already have a tracking mount and want to start on a budget in EAA. Used NV or older, but capable devices is viable too. I guess the point is that I’d like to see all forms start being inclusionary of each other’s observations but let’s all be aware of practicality of other posters budgets, experience, and attitudes and maybe no desire to try EAA as well. It doesn’t have to be for everyone, but if someone is interested then providing information is essential. No visibility of it because it gets relegated to subforums way down the list of visible forums when you log in a site, is not the best way to make it known that there is another method available. Anyway - I’ve technically stopped lurking this forum now which I’ve done for years on occasion and wanted to put in my thoughts on your new designation and split to include an observing section. Great job on trying to include everyone. Hard to please everyone and particularly with new methods. I’ve seen a lot drop out of EAA on CN and that includes NV users. We are still only a large handful. Some don’t want to post in a special section and I just find them in Observing forums. As long as the admins there continue to enforce inclusivity, we are good.
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