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What is a good NV eyepiece white phosphorous and inexpensive?

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#1 Stargazer3236

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Posted 11 May 2019 - 01:05 PM

I may dabble in NV imaging. What is a good, inexpensive, white phosphorous NV unit that can be had?



#2 Vondragonnoggin

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Posted 11 May 2019 - 01:08 PM

I may dabble in NV imaging. What is a good, inexpensive, white phosphorous NV unit that can be had?

You should define what you consider “inexpensive”

 

just a suggestion.



#3 Jim Waters

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Posted 11 May 2019 - 01:13 PM

From a NV standpoint "good" and "inexpensive" don't go together...  Do a search on Gen 2 or 2+ technologies.

 

EDIT - Stay away from Gen 1 devices.


Edited by Jim Waters, 11 May 2019 - 01:18 PM.


#4 TOMDEY

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Posted 11 May 2019 - 01:44 PM

Yeah, it's just the nature of... come to think of it, anything and everything we value. The white phosphor is a ~premium~ feature that comes at added cost, kinda like opting for Corinthian Leather for your car seats. You just won't find that as an option on an Economy Chevy Sonic.

 

BTW... If it's imaging that you want to do, the color of the phosphor shouldn't matter anyway. The information content is identical, regardless of what phosphor is in there. When processing your images, you can colorize that to anything you like! Indeed, the best camera would be monochrome, for this application.    Tom


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#5 Stargazer3236

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Posted 11 May 2019 - 03:19 PM

I found a Monochrome Armasight SDi NGV7 Gen 2+ for $1599 and an Armasight PVS7 Gen 2 for $2112 and an Armasight SD Nyx7 GEN 2 for $1599, does that sound reasonable?



#6 Vondragonnoggin

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Posted 11 May 2019 - 04:25 PM

I found a Monochrome Armasight SDi NGV7 Gen 2+ for $1599 and an Armasight PVS7 Gen 2 for $2112 and an Armasight SD Nyx7 GEN 2 for $1599, does that sound reasonable?

Those are all biocular devices with two oculars. If you plan on NV imaging, a Monocular w/relay lens is better for NV imaging. CCD or DSLR relay.

 

You would remove the visual ocular and install the relay lens and attach your camera to the relay lens.

 

Similar to this photo:

 

https://www.cloudyni...44-xp-nikon-j5/

 

I can’t attest to any quality on imaging with gen 2 systems. Maybe ask jdbastro or cnoct. Preferably cnoct as I don’t think I’ve ever seen jdbastro use a gen 2 system while imaging with his devices. Just gen 3.

 

Some devices have accessories available like relay lenses like this LRS Recon relay setup:

 

https://nightvisiono...pter_50_500.jpg

 

That one is a gen 3 system but the picture should give you more of an idea of camera connection. Can’t find any specific pics of ZWO ccd’s connected, but probably some device with ccd relay lens available.


Edited by Vondragonnoggin, 11 May 2019 - 04:31 PM.


#7 Vondragonnoggin

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Posted 11 May 2019 - 04:58 PM

You’d be better off buying this used Gen 3 Litton M944 for $1300 (it’s green phosphor)

 

https://rover.ebay.c...tm/401757052440

 

and this SLR relay that fits it perfectly for $500

 

https://rover.ebay.c...tm/352618374772

 

and Just shoot monochrome on a dslr.

 

There is one ccd relay in used condition for this Monocular but looked in bad shape for $100

 

https://rover.ebay.c...tm/153438638344


Edited by Vondragonnoggin, 11 May 2019 - 05:03 PM.


#8 Jim Waters

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Posted 11 May 2019 - 05:05 PM

You’d be better off buying this used Gen 3 Litton M944 for $1300

 

https://rover.ebay.c...tm/401757052440

 

and this SLR relay that fits it perfectly for $500

 

https://rover.ebay.c...tm/352618374772

 

and Just shoot monochrome on a dslr.

Off eBay?  Find out how many hours on on the tube and get an regional purchase receipt.  This tube must be old.  I worked for Litton ETD making these tubes and designing the power supply years ago.



#9 Rickster

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Posted 11 May 2019 - 05:14 PM

I wouldn't worry about the imaging angle.  The cameras that you already have are far better suited to that task.

 

Deciding between monocular or biocular primarily comes down to 2 things.

 

Monocular provides better image quality than biocular because biocular involves a beam splutter and additional optics.  BUT, in some cases, like mine, you may actually see better with a biocular than a monocular because you get to use both eyes.  Look thru a standard pair of binocs with one eye or two eyes to see if it means much to you.  In my case, I have floaters, which disappear when using both eyes.  Plus, and this is just my personal impression, both eyes give a much better "feeling."   To me, biocular NV feels immersive, and the FOV feels much wider.

 

The other thing is that monocular NV offers more (and better) tube selections, including variable gain.  Where as the biocular (PVS-7) is more limited.  But again, if I want the utmost in image quality, I go to the camera.  A camera will smoke even the best NV because a camera can do extended exposure, stacking and image adjustment.  NV is more about the real time experience and the feeling of having superman eyes.


Edited by Rickster, 11 May 2019 - 05:19 PM.


#10 Vondragonnoggin

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Posted 11 May 2019 - 05:17 PM

Off eBay?  Find out how many hours on on the tube and get an regional purchase receipt.  This tube must be old.  I worked for Litton ETD making these tubes and designing the power supply years ago.

Yes, off eBay. A tube can be replaced easily in the M944 if necessary later on down the road.

 

I have an M942 with used mx10160 tube from eBay. Also about 6 other NVD’s from eBay. I’ve only replaced tubes on three because I wanted either higher spec tubes or they were gen 2 mx9644 tube pvs-4’s I upgraded to mx11620 gen 3 tubes

 

My M942 still has the older gen 3 tube in it that it came with 5 years ago. I also have dslr and ccd relay lenses for it in great condition.

 

if you can find him a better imaging solution for his budget, go for it. I looked a bit for something that could couple an Intensifier with his ZWO cameras.


Edited by Vondragonnoggin, 11 May 2019 - 05:26 PM.

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#11 Vondragonnoggin

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Posted 11 May 2019 - 05:24 PM

I wouldn't worry about the imaging angle.  The cameras that you already have are far better suited to that task.

 

Deciding between monocular or biocular primarily comes down to 2 things.

 

Monocular provides better image quality than biocular because biocular involves a beam splutter and additional optics.  BUT, in some cases, like mine, you may actually see better with a biocular than a monocular because you get to use both eyes.  Look thru a standard pair of binocs with one eye or two eyes to see if it means much to you.  In my case, I have floaters, which disappear when using both eyes.  Plus, and this is just my personal impression, both eyes give a much better "feeling."   To me, biocular NV feels immersive, and the FOV feels much wider.

 

The other thing is that monocular NV offers more (and better) tube selections, including variable gain.  Where as the biocular (PVS-7) is more limited.  But again, if I want the utmost in image quality, I go to the camera.  A camera will smoke even the best NV because a camera can do extended exposure, stacking and image adjustment.  NV is more about the real time experience and the feeling of having superman eyes.

Must be some reason jdbastro uses an Intensifier with his a7s - Maybe some want to get the look of NV or reduce exposure time and still get detail. Generally a coupled Intensifier device/camera combo will greatly reduce exposure time needed and keep low iso. Could be a desirable thing. 

 

Ive only seen a few really get into it here. Most do afocal phone pics which is ok too, but a different setup. You won’t get the same results with gen 2 systems as Gavster is getting for instance. That requires a good gen 3 system.


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#12 Rickster

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Posted 11 May 2019 - 05:27 PM

Regarding cost.  Expect to pay at least 2k for a good (not excellent) one from a vendor.  If you know what you are doing, and are careful, you might snag a good used one for close to half price.

 

The main thing is to get a pic taken thru the unit.  You need to see what kind of blems it has.  All NV tubes have blems, due to manufacturing limitations.  Some have more than others.  The ones with fewer blems are more rare and cost more.  This is particularly important when buying used to avoid getting one that has a burn spot in it (such as from use in combat).



#13 Rickster

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Posted 11 May 2019 - 05:35 PM

VND,

When it comes to imaging, you gain absolutely nothing by putting an intensifier in the light path.  It does not reduce exposure time.  It is simple physics.  Cnoct has said this many times.  I am sure jdbastro will also confirm it if asked.


Edited by Rickster, 11 May 2019 - 05:41 PM.


#14 Vondragonnoggin

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Posted 11 May 2019 - 06:00 PM

VND,

When it comes to imaging, you gain absolutely nothing by putting an intensifier in the light path.  It does not reduce exposure time.  It is simple physics.  Cnoct has said this many times.  I am sure jdbastro will also confirm it if asked.

If you say so. I’m not here to argue. I was just trying to provide some links for the request. If there is no benefit from it then why use one at all?

 

my own experience with my Nikon D3300 says different and it substantially reduced exposure time. I was able to take shots of Ha targets in sub 1 second with Intensifier and without Intensifier nothing showed up. On a manual mount no less.


Edited by Vondragonnoggin, 11 May 2019 - 06:02 PM.

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#15 11769

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Posted 11 May 2019 - 06:09 PM

I found a Monochrome Armasight SDi NGV7 Gen 2+ for $1599 and an Armasight PVS7 Gen 2 for $2112 and an Armasight SD Nyx7 GEN 2 for $1599, does that sound reasonable?

Pass. Not a good use of money. Going with a green tube will be more cost effective and also offer a slight overall increase in overall "system" performance when the response of the human is included. Doesn't apply to phone imaging or the best white phosphor tubes of course. 



#16 Rickster

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Posted 11 May 2019 - 10:51 PM

If intensifiers were good for imaging, Hubble would have one, the pro astronomers would use them, the guys on the AP forum would be using them, etc.  But it doesn't matter.  NV has something even the best imagers don't have; magic.  If you show a kid your best EAA image at a star party, what is his reaction?  He is going to ask why you go to all the trouble when you can get a better image off the internet.  Right?  We have all heard it.  But hand them night vision, and they are speechless.  You don't even have to point them to anything.  They get it.  This thing is magic...in their hands...and they don't want to give it back.  Mom and dad are going to hate you because they are going to get asked all the way home why he can't have one.

 

So, David.  Judging from a couple of your posts, you are in to sharing your love of astronomy, right?  Well I can't think of a better way than NV.  Please don't be turned off by the NV images that we have all seen.  They do not even remotely do the NV experience justice.  It is kind of like the difference between looking at a picture and looking at virtual reality.

 

And VND.  I apologize for being so blunt earlier.  You have tons of experience with almost every NVD ever made.  David is lucky to have you, and the other NV guys to help him pick the right one.  As I am sure he is discovering, it isn't easy.


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#17 Vondragonnoggin

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Posted 11 May 2019 - 10:56 PM

Thanks Rick. I apologize too if I came off as dismissive.

 

EAA should be one big happy family, even if some differences of opinion.

 

smile.gif


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#18 Vondragonnoggin

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Posted 11 May 2019 - 11:28 PM

These systems are usable as a Monocular, has built in c-mount, has ccd relay for converting visual Monocular to ccd camera extension, can put a nosepiece on the c-mount if needed Prime Focus or attach c-mount capable lenses (either native or c-mount to your favorite lens brand via adapter).

 

https://pyramidimagi...oScope 8000.pdf

 

Unfortunately they are not inexpensive and the gen 3 tubes aren’t very performance oriented. Much better gen 3 tubes can be had in newer pvs-14’s and Mod 3C housings being used be members here. It’s biggest attraction is the versatile configuration and accessories for using with a camera. I think a FOM1600 tube spec would be better for narrowband than the gen 2+ systems that were under consideration by the OP, but cost/performance ratio is not very good. I would doubt these are a quick or easy tube switch, but I may be wrong. Someone else might know more about them.

 

Maybe there are some relays available for the Mod 3 housing I’m not aware of.



#19 t_image

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Posted 12 May 2019 - 12:39 AM

If intensifiers were good for imaging, Hubble would have one, the pro astronomers would use them, the guys on the AP forum would be using them, etc. ..................

When it comes to imaging, you gain absolutely nothing by putting an intensifier in the light path.  It does not reduce exposure time.  It is simple physics.

I'm confused by your posts? If you are relenting on your point, you haven't done a good job.

 

Here's some math:

a realtime video has usually 30 frames per second with an exposure of maybe 1/30 or 1/60.

One can record content in video with NV in the train that collects light that can't be seen with a camera without the NV in the optical train.

How does that not relate to exposure time???

So you might want to re-think your argument.....

There is a domain of usefulness with NV in the 'light path' that a camera alone and long exposures cannot accomplish and it shouldn't be downplayed, especially in the EAA section of CN.

 

And you are equivocating on the term 'imaging' to support your point.

In the context of a EAA forum,

not an AP forum,

you might be careful to make statements that might confuse other readers and lead them to believe there is no value in connecting a NV tube device to an electronic sensor to archive the scene....

"imaging" also include realtime video of events.

Those tracking meteor showers have utilized NV tubes for years in their imaging train.

https://www.amsmeteo...ideo-observing/

There are many other advantages, but it is all about matching the usefulness of a tool to a user's requirements....


Edited by t_image, 12 May 2019 - 12:40 AM.

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#20 jdbastro

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Posted 12 May 2019 - 12:40 AM

VND,

When it comes to imaging, you gain absolutely nothing by putting an intensifier in the light path.  It does not reduce exposure time.  It is simple physics.  Cnoct has said this many times.  I am sure jdbastro will also confirm it if asked.

I guess I should respond.

 

Simple Physics says:  An image intensifier (Gen 3) provides at least 55-65K electronic amplification before the camera sees anything (known as Luminous Gain).  A conventional EAA configuration without an intensifier has 0 elect amplif in front of the camera.  That's a serious benefit to intensified astro image capture.  Now there will be a relay lens or macro lens required to capture the intensifier's phosphor screen but the light losses from such a lens are a tiny fraction of that elect. amplification.

 

So indeed, exposure time is much reduced for astro image capture when using an image intensifier (specifically Gen 3).  I have proved this to myself over and over again.  Less exposure time means less accurate tracking necessary and little need for auto-guiding.  And since I'm pretty lazy, No need for post-processing of multiple images (aka stacking) when the night is over.  An image intensifier allows excellent astro target image capture with a single exposure often times within 30 sec or less.

 

Downsides to using an NV device vs conventional EAA (camera only):  Modern digital cameras likely capture in higher resolution than a modern image intensifier, and of course, the intensifier adds extra cost with the trade-off of less accurate required tracking.  Oh, then there's that monochrome vs color thing that NV can't compete with.


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#21 cnoct

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Posted 12 May 2019 - 01:49 AM

VND,
When it comes to imaging, you gain absolutely nothing by putting an intensifier in the light path.  It does not reduce exposure time.  It is simple physics.  Cnoct has said this many times.  I am sure jdbastro will also confirm it if asked.

 

 bigshock.gif Really! 

 

If image intensifiers didn't reduce exposure time, I certainly wouldn't be exclusively using them for all my NV astro captures, both video and stills. 

 

I and my NV astro digital footprint disagree with you!
 
 


Edited by cnoct, 12 May 2019 - 08:51 AM.

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#22 t_image

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Posted 12 May 2019 - 10:27 AM

Great to hear from the heavyweights of NV imaging!

As a side note physics does describe the limitations of both methods, whether camera alone or intensifier in front of camera.

The key is how much signal can be drawn out while still being above the noise floor (noise has different sources)....

 

I imagine in describing long exposure imaging or EAA live stacking software integration methods,

that there may be a threshold where a camera could exceed the ceiling of what can be achieved with a intensifier in front (given certain conditions).

 

Since an intensifier has an amplification effect displaying on the phosphor screen both signal and noise.

I would imagine that there would be an exposure limit here where the noise of the tube screen might eventually overwhelm a signal at some exposure threshold,

while a well-tracked long exposure camera at a very dark site where the sky brightness would allow a tremendously long exposure if tracked well might catch up to amplification gains, and then surpass the intensifier exposure ceiling.

 

But I would also think this would occur at quite long exposures for a camera alone that would require tracking with mounts of 4-digit price tags $$$$/+guide camera, and require very dark skies,

something that doesn't always seem desirable to the regular EAA individual.

...And this might be past the saturation point of most all targets (especially intensified) except maybe the faintest dark nebula???

I also concede that real experience may crush this thought experiment out of practicality.

 

I guess a simple experiment would be is with ideal setting on intensifier(reduced noise on screen), how long an exposure would it take before the noise (say from period scintillation) formed an entire blanket across the image (pointed at only the faintest source-could even be terrestrial so no tracking needed)? But even then this blanket would have to be brighter than the faint accumulation of a very faint target.....

If the given intensifier tube captures the same one-shot image in __seconds as an (for ex:) Sony a7s alone (high ISO?) does with same optics in __seconds (longer),

then a quick multiplier could be roughly considered.

Then multiply this intensifier noise limit exposure length found by the multiplier, it will give an approximation of the exposure time where the camera alone has to wait to reach said limit. With this data, one could approximate how dark one's sky would have to be to afford the one-shot exposure to achieve this (also presuming an excellent tracking setup)...

Of course then one could say: well shorten the camera alone exposures and then just take many subs and stack to get the integration time,

but then the same strategy could be done with the intensifier, which would also help eliminate the cumulative phosphorus screen noise if processed well...

All complexities. Nothing one could state firmly.....



#23 Rickster

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Posted 12 May 2019 - 02:03 PM

The purpose of this thread is to help "conventional" EAA practitioners find a good NVD to venture into NV astronomy. 

 

And then the subject of imaging via NV came up.  For that consideration, I think that jdbastros image gallery should be sufficient to let anyone decide if his approach will give them the images that they are seeking.  Those images represent the best to be had with high grade gear from a dark site located on top of an 8800ft mountain (mount Pinos).  In addition, Cnoct has posted numerous videos on youtube that represent the video quality available with high grade gear.

 

I see no need to go further than that to make my point, except to address the physics for those who like physics.  JDBs rig, as he described it above, basically uses NV as a preamplifier.  Preamplifiers make a lot of sense if the final amplifier has inadequate sensitivity or gain.  In the case of EAA, readily available mono camera sensors are as sensitive as NV sensors.  And, once the signal is digitized, gain is unlimited because gain is a simple arithmetic operation once the signal is digitized.  Further, even if one could find an intensifier sensor with marginally more sensitivity than a camera sensor, there is another, even more important consideration.  Each additional layer added to the imaging train introduces noise which statistically accumulates in the image according to the square root of the sum of the squares rule.  This noise accumulation is readily apparent in the images and videos from the NV heavy weights.  This noise is important because signal to noise ratio is the ultimate measure of image quality.  The bottom line is that adding a NV intensifier to an imaging train degrades image quality by reducing the signal to noise ratio. 

 

And if one needs additional examples of how added layers of amplified noise can adversely impact clarity, they need look no further than the posts of the contrarian, above.

 

I rest my case and will let the readers decide from here.

 

So now that I have you here, would one of you NV heavy weights please help the conventional EAA practitioners identify a good introductory NVD?



#24 Gavster

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Posted 12 May 2019 - 02:37 PM

The OP stated in his first post that he was considering a dabble into NV imaging. I think it would be helpful to confirm what he means by this. Is it to use NV to take actual images of DSOs or is it just to use NV in the conventional way of live eyepiece views with no camera attached.

 

If the latter then I think there’s a lot of posts on this section that cover this. Basically go for the best gen 3 (I know some gen 2 are good, I have one but I prefer gen 3) and make a choice re manual gain, White or green etc.

 

However if the OP actually wants to take images using NV then it’s a different question imo. For my NV images, I just want a quick and easy way to record my visual observations for posterity. I know my images are never going to win any AP competitions but I really like the ease with which I can take phone photos and I don’t have to do any post processing etc which I understand is the most labour intensive and key part of normal AP. I find NV imaging a lot of fun and I have never (nor do I think I will ever) do normal AP. For NV imaging, the mount, filters, camera are all at least as important as the nvd used.


Edited by Gavster, 12 May 2019 - 02:52 PM.


#25 Vondragonnoggin

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Posted 12 May 2019 - 03:01 PM

I’m done here. To the OP - good luck. I think the request is difficult with gen 2+ and finding systems with relay lenses available new for that budget.




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