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NV with only GEN 3?

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#1 rml63

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Posted 18 October 2016 - 07:10 PM

Hello All,

I have been reading with interest the nv experience of Eddgie and et al.  However, I was wondering does the monocular have to be Gen 3 spec or will a 2+ version still work?  I realize this is a very basic question , but astronomy and nv are new to me.

 

Ps.

If someone could just list the parts required or a novice option (so I could research more and understand it) that would be great.

 

Thanks

Mike



#2 rml63

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Posted 18 October 2016 - 09:24 PM

I just found Peter Wangs site , that cleared things up

 

Mike



#3 pwang99

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Posted 19 October 2016 - 12:10 AM

Great! That site is very much a work in progress, so if you have any suggestions about how to improve it, please let me know!



#4 cnoct

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Posted 19 October 2016 - 03:02 AM

I'm super curious to know as well, hopefully Eddgie and pwang99 will provide some solid insight on the matter.
 
Being that I use multi alkali S20/S25 (G2) image intensifiers and GaAs/GaAsP/GaAlAs (G3) based image intensifiers for astronomy, I'm all the more curious about the information Eddgie and pwang99 will use to substantiate their stance regarding multi alkali image intensifier technology, particularly as it relates to night vision astronomy. 
 
What information on pwang99's blog cleared the matter up?
 
I read the blog and haven't found any substantive data as to why multi alkali S20/S25 (G2) technology has no merit for night vision astronomy. The only mention of technology types was regarding (G3) where it was stated that one "has to use at least a third generation tube to see anything of merit."
 
There seems to be a technology disconnect, as I noticed pwang99 seems doesn't reference image intensifiers but instead refers to photodiode based photomultiplier tubes, a similar but distinctively different technology from image intensifiers.
 
It certainly could be the case that pwang99 is using photomultiplier tubes instead of image intensifiers which could explain the statements regarding photocathode technologies and might explain why he states the following:
 
"Fundamentally, Night Vision Astronomy is about using a high-quality, latest-generation ("Gen3") night vision device to amplify light. These devices have an analog (not digital) photomultiplier tube, which is able to make a dark night almost look like daytime. These have been produced as military and tactical devices, and as astronomers we can benefit from the innovation here."



#5 Eddgie

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Posted 19 October 2016 - 09:06 AM

Hello Mike,

 

I would defer to Cnoct on all things to do with tube performance and what would be suitable for use.  When people contact me regarding questions about tubes, I refer them to Cnoct because he is kind enough to assist them and I do not have sufficient knowledge to provide any confidence in my own recommendations.

 

I have indeed enjoyed using NV for astronomy far more than I have any other kind of traditional gear and there are numerous ways to get started, and whichever way you go, I hope that you have as much fun doing it as I am having!

 

Have a great day!


Edited by Eddgie, 19 October 2016 - 09:07 AM.


#6 Vondragonnoggin

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Posted 19 October 2016 - 09:48 AM

Speaking of parts required - while searching ebay I have some various night vision searches setup. One of them is for "night vision afocal" and up pops items including, but not limited to:

 

pvs-7 a/c c-mount adapters (5 of them were available)

pvs-7 b/d c-mount adapters (quite a few of these too)

 

a couple products in adapters from Raf camera (love my ENVIS lens 1.25" adapter!)

 

and some (of course) very nice afocal lenses.

 

while searching for night vision intensifier, up pops a Fijinon Stabiscope 10x40 IS Day/Night binocular with detachable oculars in two pairs - one of the pairs is gen 2+ oculars. About $4.5k

 

if I only had the extra money right now...


Edited by Vondragonnoggin, 19 October 2016 - 09:51 AM.


#7 outofsight

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Posted 19 October 2016 - 01:53 PM

For the OP, in general, why do most of us just recommend Gen 3, in general, because that's all we know and we know it works, we feel safe recommending it. But all Gen 3 isn't created equal either, there is a broad continuum in all of this night vision (NV) device stuff, a lot of it is sometimes hard to figure out, or compare.

 

But for many of us who have used the Gen 3 NV, we know it works, but many of us have never personally seen any Gen 2 stuff to compare it to, so we recommend what we know and what we know that surely works. We wouldn't want to recommend something to you and have you blow $1500, or $2000 or $3000 on it and have it not work. 

 

So, in essence, Gen 3 is just a no brainer (especially for those of us who have never seen a Gen 2 device or used one for astronomy). And, although I've been reading about NV for about a year now, I can't count on one finger a highly recommended Gen 2 device for use in astronomy, now that is "only me" and my NV knowledge is fairly (to say the least) limited, but I hope that gives you an idea, though maybe somewhat incorrect, of why many of us just limit ourselves to Gen 3.

 

Having said the above, if Cnoct recommends something, you simply take his advice, or at least put it at the top of the list as truly accurate information.

 

I used "we" a lot, but these are only my thoughts on why Gen 3 is recommended as a surely safe bet and Gen 2 isn't discussed much. (Another reason I don't discuss Gen 2, besides just not knowing, I see many Gen 2 devices on eBay that are priced the same as Gen 3, or not significantly lower.)



#8 PEterW

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Posted 19 October 2016 - 02:37 PM

You want the best performance you can find (and afford)... ultra filmless white for those who can and sliding down gen3 for the rest of us. At some point the tube won't help much more than eating a pile of carrots... I had a gen1 and it wasn't much use for anything apart from killing my night vision. As I say to people "it's not cheap and it's not for everyone, but those who have them are happy to share, so you don't need to all get your own".

Cheers

Peter

#9 rml63

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Posted 19 October 2016 - 10:06 PM

Hello All,

Thanks for all of thr replies.  Cnoct:  Peter's sight gave a shopping list of what parts to start purchasing to build a nv eyepiece.  Or at least that is how I took it.  Is there an easier way to figure out what a novice should buy to build or perhaps purchase an already assembled nv monocular?

 

Mike



#10 Vondragonnoggin

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Posted 19 October 2016 - 10:55 PM

Hello All,

Thanks for all of thr replies.  Cnoct:  Peter's sight gave a shopping list of what parts to start purchasing to build a nv eyepiece.  Or at least that is how I took it.  Is there an easier way to figure out what a novice should buy to build or perhaps purchase an already assembled nv monocular?

 

Mike

You might have a difficult time with listed vendors that are just US based. Many night vision devices and parts are non-exportable due to ITAR laws.

 

The good news - ebay.ca plus a few other Canadian dealers sell gen 3 night vision, but you might have to post links on items you find to verify if a good candidate as a night vision eyepiece for telescope use.


Edited by Vondragonnoggin, 19 October 2016 - 11:01 PM.


#11 Rickster

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Posted 20 October 2016 - 12:26 AM

cnoct posts on a night vision forum as stanley.  The gen2 vs gen3 debate has been going on over there for many years.  I don't know if it is ok to post links to another forum, so I will post an excerpt from one of stanley's 2011 posts.  If you are any good at all with google this should provide a trailshead to get you more information.  If either cnoct or the mods do not think this post is appropriate, just let me know and I will promptly delete it.

 

posted by stanley

Here are some important difference between all gen 2 (+ or not) and all gen III tubes. The main differences between them, is the wavelength ranges they are sensitive to.

Gen 2 tubes use a multialkalai photocathode and have their peak sensitivity in the visible range, with the range of most useful sensitivity from 400 to 600 nm. The total range of sensitivity is limited at short wavelengths by the glass envelop at about 325nm. On the long wavelength end the sensitivity trails off to about half of peak by 700 nm reaching zero useful sensitivity at about 1000nm.

Gen 3 tubes use a Gallium Arsenide photocathode. They generally have their greatest sensitivity in the 700 to 900nm range. GaAs is also inherently limited at the short end by the glass envelope, but many tubes are manufactured which purposely suppress the sensitivity in the visible range to improve the ability to see through haze in moonlight. For those tubes the useful range is from around 550 nm to 950 nm where GaAs cuts off sharply. There are some Gen3‘s doped to give response to 1100nm, but they are noisier than other tubes and don’t give better dark performance. They are used when being able to use light from YAG lasers at 1064nm is required.

Whether a G2+ or G3 tube will give better apparent performance depends more on the illumination present and the tube construction. In either tube, the resolution is determined by the following, not the photocathode material:

1) input faceplate material
2) micro channel plate
3) focusing distance between components
4) thickness and particle size of the phosphor material

Gen 2+ will give better performance when the illumination comes primarily from sources, which have mostly visible energy. Such sources include dawn and dusk sky glow, moonlight, (which is just reflected sunlight) and light from local artificial sources like residential or highway lighting and distant towns or cities. In some parts of the world, like most of Europe, Japan, and most of the coastal regions along the eastern seaboard of U.S. In the aforementioned location, you can‘t get away from artificial light as the primary illumination source.
On moonless nights in rural or ocean areas of the world the situation changes. The primary source of illumination is from sky glow resulting from high velocity solar particles striking the upper atmosphere. That is the primary source of sky brightness on moonless night. It is several times brighter in the 700-1000 nm infrared range than the sum off all visible starlight and sky glow. . For that Gen 3 makes the most efficient use and in those conditions gen 3 tubes (regardless of resolution) will have better sensitivity and signal/noise than gen 2+. That‘s why they‘re used extensively in aviator goggles and by the US military, which can‘t count on artificial illumination being available.

So which is better? That depends on where you are and the available illumination. Hence, it‘s not a question of one being better than the other, only more suitable.



#12 cnoct

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Posted 20 October 2016 - 04:46 AM

Well that borders on super creepy!

I know of one other guy who was into this sort of thing, creeped me and a bunch of others out.
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#13 cnoct

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Posted 20 October 2016 - 05:10 AM

Cnoct:  Peter's sight gave a shopping list of what parts to start purchasing to build a nv eyepiece.

Mike


Ah, so you were able to find the information pertaining to your main question regarding image intensifier technologies.

I myself have yet to find out why night vision astronomy is the exclusive domain of Gen 3 'photomulipliers', any chance you could share the information that cleared this up for you.

FWIW: The highest performing Gen 2 image intensifier I currently use for astronomy has a figure of merit of 2296 (SNR of 32.8 and Resolution of 70lp/mm). Metric wise, it beats most of my Gen 3 tubes and produces some pretty impressive views.

Didn't know pwang99 had compiled a list of system components needed to build up a complete night vision system. Though I read his blog, the component list seems to have eluded me, can you post a link.

#14 Rickster

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Posted 20 October 2016 - 10:14 AM

Maybe this will relieve some of the creepiness.  Or make it even creeepier. 

 

From a 2011 cnoct post at this forum.

 

I post most of my photo's over on http://www.nightvisi...ewforum.php?f=9 since that forum is dedicated to night vision. I post as Stanley over there, so just look for all my posts.


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#15 Vondragonnoggin

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Posted 20 October 2016 - 10:26 AM

Maybe this will relieve some of the creepiness.  Or make it even creeepier. 

 

From a 2011 cnoct post at this forum.

 

I post most of my photo's over on http://www.nightvisi...ewforum.php?f=9 since that forum is dedicated to night vision. I post as Stanley over there, so just look for all my posts.

Well, creepy or not, it's good to see others gathering info from other sources instead of staying within a closed system. At least you followed the posts of someone knowledgeable. Less misinformation propegated.

 

Check out posts from cj7hawk too. He briefly posted here on the p8079HP gen 1 cascade tube DIY eyepiece, which is a whopping big, but great tube for astronomy. Tons of gain and EBI is not bad at all. His posts are also very informative. 

 

Oops, maybe I'm being creepy now too. 

 

:shocked:


Edited by Vondragonnoggin, 20 October 2016 - 10:27 AM.

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#16 pwang99

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Posted 20 October 2016 - 12:10 PM

Hey guys! I've been on the road for work, didn't realize all the confusion my site would cause! :-)

Cnoct and others clearly know much more about the details of the NV technology and the differences between the generations. I see my role as mostly being a scribe and curator, with a little bit of editorializing thrown in. The comment about gen2 vs gen3 was based on reading numerous posts on here as well as some other websites. I wasn't aware of anyone strongly recommending gen2 tubes, and earlier in the year as I did research prior to purchasing my pvs7, there were several folks that emphatically stressed getting a C or D tube.

My goal with my small site was to provide a single, neophyte-friendly place for people who were curious about modern astro NV. I'd like to make it more comprehensive over time, but the reason I point people to other resources is because I know I don't have the time to build out the end-all be-all site for astro NV. :)

Cnoct if you'd like to write up a couple of paragraphs I could put into the FAQ about gen2 vs gen3, that would be much appreciated!

Edited by pwang99, 20 October 2016 - 12:11 PM.


#17 rml63

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Posted 20 October 2016 - 05:22 PM

Yes I was able to find some basic information about nv technologies, as Peter pointed out his website was built for novices like myself.  Someone with your advanced knowledge of the subject must have be able to see that?

 

Mike



#18 cnoct

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Posted 20 October 2016 - 07:21 PM

Well, creepy or not, it's good to see others gathering info from other sources instead of staying within a closed system. At least you followed the posts of someone knowledgeable. Less misinformation propegated.
 
Oops, maybe I'm being creepy now too. 
 
:shocked:

 
No, Rickster got the creep factor, your just a bit off  ;) 

The misinformation is propagating at an alarming rate, it's puzzling why there's such an appetite for willful ignorance.
 


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#19 cnoct

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Posted 20 October 2016 - 07:51 PM

Yes I was able to find some basic information about nv technologies, as Peter pointed out his website was built for novices like myself.  Someone with your advanced knowledge of the subject must have be able to see that?
Mike

 

I still can't find the information on the blog regarding the technology differences nor the list of system components needed to build up a complete night vision system, link please.

There seems to be no mention of the various image intensifier technologies, just the in fact statements that one must "use at least a third-generation tube ("Gen 3") to see anything of merit" and "Fundamentally, Night Vision Astronomy is about using a high-quality, latest-generation ("Gen3") night vision device to amplify light. "

It is obvious, though not necessarily to a novice, that the blog was written by a novice. I see nothing wrong with that and have no issue with that.

 

However, if the blog is intended to guide/educate novices, would it not then be all the more important for the content to be factual and accurate?

 

There would seem to be a greater burden of responsibility when writing for the novice, regardless if the author is a novice or not.

 

 



#20 JMW

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Posted 20 October 2016 - 09:05 PM

I read these threads and dream that someday it will be a simple task to go to Astronomics or other astronomy vendor web site and get a great NV devices with the accessories to attach it to the focuser.  I am willing to wait a few more years for the technology to become better, easier to buy and use. 

 

I also love to backpack and I think a handheld NV monocular with a small objective lens would be the lightest possible astronomy equipment that would be useful to carry on a backpacking trip. I currently carry a 8x42 monocular for day time navigation or very casual astronomy.



#21 Vondragonnoggin

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Posted 20 October 2016 - 09:30 PM

In all honesty, it was not that difficult to find parts or suppliers. The problem has really been telling myself I really don't need another NV device....

 

There are links in various theads, other website forums, CN article on Night Vision 2015, etc that coupled with some reading, some questions here, really can get you started quickly.

 

I always figure the more I study the technology, the better the experience will be (has proved so to me), and the easier I can identify systems that are good candidates for astronomy and get better deals on equipment (also has proved so to me).

 

A turn key astronomy solution is not really available now, but comes pretty close with only a couple purchases.



#22 Eddgie

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Posted 21 October 2016 - 09:21 AM

I read these threads and dream that someday it will be a simple task to go to Astronomics or other astronomy vendor web site and get a great NV devices with the accessories to attach it to the focuser.  I am willing to wait a few more years for the technology to become better, easier to buy and use. 

 

I also love to backpack and I think a handheld NV monocular with a small objective lens would be the lightest possible astronomy equipment that would be useful to carry on a backpacking trip. I currently carry a 8x42 monocular for day time navigation or very casual astronomy.

 

It takes one part to attach a device with C mount to a focuser and that part is available right now from Scopestuff.

 

http://www.ebay.com/...GsAAOxyOMdS6T62

 

If you wait for the major vendors to start stocking NV gear, you will likely be waiting for a very, very long time.  Most of them will see this as a specialty item that few amateurs will want to buy and they will not be able to add any value over what the NV dealers can already do.

 

Outstanding for back packing and camping!  I never go out in the dark without a piece of Night Vision gear.  

 

And a monocular with a 3x lens makes a jacket pocket system that I think is the ultimate grab and go astronomy tool.

 

NVD with 3x afocal lens.jpg

 

While it might seem expensive, for most people, it has made a lot of seldom used gear look so unappealing that they wind up selling a lot of stuff that they know they will probably never use again.   I sold a load of expensive eyepieces.   Boring after using NV.


Edited by Eddgie, 21 October 2016 - 09:23 AM.

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#23 pwang99

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Posted 21 October 2016 - 09:22 AM

 

I still can't find the information on the blog regarding the technology differences nor the list of system components needed to build up a complete night vision system, link please.

 

I think he was referring to: http://pwang.io/hobb.../nvbuyersguide/

 

 

 

It is obvious, though not necessarily to a novice, that the blog was written by a novice. I see nothing wrong with that and have no issue with that.

However, if the blog is intended to guide/educate novices, would it not then be all the more important for the content to be factual and accurate?

There would seem to be a greater burden of responsibility when writing for the novice, regardless if the author is a novice or not.

 

Yes, absolutely!  I sincerely appreciate the information and feedback you've provided on this thread and the other thread.  I will try to set aside some time this weekend to update my site.

 

For background: the reason I created the site was because I felt that more and more people were getting interested in NV astronomy, and various of us kept having to repost the same links over and over to posts and threads here on CN.  I threw my site together over a few days because I wanted a place to collect all the information I had gathered, as incomplete as it might be.  (Also there was a time critical component, since I had loaned my Mod3 to someone to take to Okie Tex, and he wanted a simple URL to give to people who wanted to know more.)  Unfortunately, since that time, I've been traveling nonstop for work, and I haven't had the time to update the site.



#24 Eddgie

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Posted 21 October 2016 - 09:30 AM

And here is perhaps the most telling argument against using an astronomy vendor.

 

They simply will not get the volume of business to let them see a sufficient number of tubes to allow them to pick an excellent tube from a good tube.

 

People like Ident Marking, Ultimate Night Vision, or Night Vision Depot do a big volume of business and they can cherry pick the right tube for you.  If you want a tube with a high spec and have patience, they will find it for you.

 

Orion or Astronomics will just want to deal with complete systems purchased in bulk from a big supplier like ATN or Armasite. 

 

In my own estimation, you are now and probably forever will be better off buying a C mount device from a company that deals heavily in night vision gear.  You will get the best possible if you follow that route.

 

If you go with a used PVS-7, it takes two parts to make it work with a telescope and no tools or special equipment is needed to install them.   It is as easy as screwing a Barlow lens on to the front of a diagonal. 


Edited by Eddgie, 21 October 2016 - 09:35 AM.


#25 Rickster

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Posted 21 October 2016 - 09:55 AM


Check out posts from cj7hawk too. He briefly posted here on the p8079HP gen 1 cascade tube DIY eyepiece, which is a whopping big, but great tube for astronomy. Tons of gain and EBI is not bad at all. His posts are also very informative. 

 

 

Yes, I agree.  cj7hawk has graciously shared a lot of knowledge regarding night vision.  He also contributes on the ar15.com night vision forum.




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