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PVS-7 on the way!

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#1 Eddgie

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Posted 01 July 2020 - 03:50 PM

I gave up on PVS-7s a few years ago because it was almost impossible to find one with a really high quality tube.  As much as I like using both eyes at the telescope, every PVS-7 I have owned simply had too much noise for my liking.  

 

I remember being out at Mansfield dam a few years ago with my last PVS-7 and comparing the view with my Micro with F9800 tube. I could see Barnard's loop easily and brightly in my a single Mod 3 but when I used the PVS-7, while I could see the loop pretty easily, the view was extremely grainy.   Now without narrow pass filters at 1x, I thought the standard PVS-7 did a really nice job, but when used in my 12" F/4.9 with a long pass filter on galaxies, the noise was just a bit to much to give really enjoyable views of galaxies.  

Now two or three years ago (time flies!) there was a small lot of PVS-7s sold with filmless white phosphor tubes.  At the time, I was on the fence about it so I tarried on getting one.

 

One night Peter and I went to Mansfield dam (after he had sorted his PVS-7 out. It was purchased in a PVS-7 A housing that had a lot of issues and he rehoused it into a PVS-7 B/D) and had some time to use the re-housed PVS-7.   It was wonderful. I was really impressed with the view. It was the first time that I had ever used a PVS-7 that fully pleased me.   The view was crisp and bright, and very quiet. 

 

Time goes buy and I was PMed by a CN member yesterday that had bought one of these when they became avialable, and he was wanting to know if the price was fair.  Now at the time, I did not realize it was one of the filmless tube PVS-7s.  He had provided a spec for the SN of 24.1 or something and I thought it was a thin film tube so I was not so interested, but I did know someone that was looking for a PVS-7 and forwarded on to the other individual.  

During the email, the other individual pointed out that the SN was actually over 30.  There had been a copy of the spec sheet in seller's original PM, but as it turns out, he had apparently transposed the minimum SN date in the text of his note (with the other figures like .3 EBI and such) and when I went back to look at the spec sheet, I realized it was one of the L3 filmless tubes.  

 

Since I had already pointed the other buyer to it, I did not fell like I should go steal the sale from him, but I told the seller if the other buyer passed, I would take it.  About 18 hours later, one of the unicorn filmless WP Unicorn PVS-7s is on its way to me.  How fun for me!

 

One of the biggest problems with a full NV binocular is that it is very hard to get more than 3x and a zoom lens is of course not really possible.  I think this unit will pair really well with my 70mm to 210mm zoom. I also really look forward to using it in my 12" dob and with the zoom lens.  I mostly run with full gain, so for me, the absence of a gain control is not really that important. 

 

Some thoughts  on binocular summation as it applies to the PVS-7 and full binocular... 

 

A Mod 3 (or other binocular) has two image intensifiers and the random scintillation and noise patterns are different, so the brain kind of averages these artifacts out of the view all by itself, and with a full binocular, I do believe you get a very meaningful boost in perceived signal to noise ratio.  There is nothing like using a full  binocular.

 

The PVS-7 though uses a single tube, and both eyes see the exact same pattern, and because if this, I don't feel like one gets the same perceived signal to noise ratio benefit that is provided by a full binocular. I do believe that there is some slight improvement, but my subjective opinion is that it is not nearly the same as using a full binocular.

 

The brightness penalty of a standard binoviewer is not present in a PVS-7.  The output brightness of a PVS-7 would not be any different from two single monoculars because the tube itself is set up to provide a minimum luminous output to each eyepiece so there is no real penalty here.

 

The last attribute of binocular summation is visual acuity.  Just like with a standard binoviewer, the PVS-7 allows the users to use both eyes and just like with a standard binoviewer, the image will look larger than it would using one eye, and the visual acuity will be improved.  This is independent of the SN issue because while there is only one image shared by both eyes, this is analogous to getting an eye exam and viewing a single visual acuity chart at a distance with one eye, then the other eye, then opening both eyes and noting an improvement in the sharpness of the letters on the vision test chart.  

 

I am very happy to have the good fortune to get one of these unicorn PVS-7s.  I have often wondered if I could find one, if it could or would displace a monocular as my primary telescope observation device.  This unit does not have the SN of my best monocular, but it is very similar in specs to my first filmless tubes in my original Mod 3 binocular, and that worked quite well for years for me in my telescope as far as performance goes, so I am looking forward to seeing if the improved visual acuity and low EBI offsets the better SN of my best monoclar. 

It was a real surprise to me to see one of these become available.  I thought having pointed it to another CN member, it would escape me, but the Matrix must have wanted me to have it.

 

Weather his is not great with more dust expected in coming days, but the first chance I get, I will give some A/B comparisons in the telescope. 

 

Hope you are all doing everything you can to stay safe. Remember, it is very dangerous out there. I appears that a lot of people out there may not be that interested in protecting you, so protect yourself. 

 

 

 


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#2 tcc

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Posted 01 July 2020 - 04:45 PM

I have a Harris thin-filmed PVS-7 with decent specs. Have considered many times getting a Mod3 for the higher performance of the L3 filmless tube but in the end, I decided I prefer 2-eye viewing with higher magnification camera lens and when using telescope.

 

So really looking forward to your report on your PVS-7 with L3 filmless tube.


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#3 Mazerski

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Posted 01 July 2020 - 04:58 PM

Ed,

 

I have one of those PVS7 WP units from Glynn and my guess is the tube specs in both units may be similar. 
 

== hand held with 642nm IR filter to view the Milky Way clouds with 135mm f/2.8 does really well

you will clearly see nebulosity of M17 and M8. 
 

== in scope, try the 642nm filter on M42. It looks great... not as much nebulosity but bright with a lot of stars over Ha filter.

 

== can’t say if this is specific to me but at scope, if I cover one eye with hand and keep eye open, the view with single eye approaches that of Mod3. Meaning, the resolution improves and the scintillating decreases. Trick of the eye? Maybe but try it.



#4 tcc

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Posted 01 July 2020 - 05:07 PM

A question: Why is it that no US vendor is selling PVS-7 with L3 filmless tube?



#5 Eddgie

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Posted 01 July 2020 - 07:22 PM

A question: Why is it that no US vendor is selling PVS-7 with L3 filmless tube?

It would only be speculation on my part, but that speculation would be that there is not much of a market for them.

 

The US Military has not purchased PVS-7s in a long time, and since they were the primary consumer of the 10130 format tube, when they stopped buying them, production trickled off. 

Sportsmen went to the PVS-14 long ago, and now they are moving to thermal, so they have little interest in spending that much money for "just" a PVS-7.  They would spend that money on thermal sights.

 

We constitute a tiny fraction of a tiny fraction of the total market for night vision gear and we are not even noise on the radar. 



#6 joelin

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Posted 01 July 2020 - 08:45 PM

Can one assemble a WP PVS-7 using an empty case and a top end WP tube?

 

How would a top end PVS-7 + telescope compare with dual MOD 3-C's + binovewer + telescope? 



#7 Eddgie

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Posted 01 July 2020 - 10:01 PM

Can one assemble a WP PVS-7 using an empty case and a top end WP tube?

 

How would a top end PVS-7 + telescope compare with dual MOD 3-C's + binovewer + telescope? 

The PVS-7 is easy to build but you can't use just any tube.  The PVS-7 takes an F9810 format tube, while the PVS-14 takes  an MX111769 tube.  They are different packaging.  But but assembling a PVS-7 from a kit is super easy. Finding a really high performance tube in the F9810/10130 format is hard. 

 

If you were to find one, there would be no contest,  Using two Mod 3s in a binoviewer imposes major performance limits.  Not sure why anyone would want to do that. I mean yeah, you would get to use two eyes, but you are working at a brightness level equivalent to double the focal ratio and unless the scope is maybe f/8 or so, you are losing a lot of field illumination.  It is not really a good use of $9000 to put two Mod 3s in a binoviewer. To reach focus without using a Barlow or GPC is very difficult and even if you can, f/7 is about as fast a scope as you would want to use, and your monoculars would be working at a brightness of f/14 each.   Not sure why one would want to do that. 


Edited by Eddgie, 01 July 2020 - 10:07 PM.

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#8 joelin

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Posted 02 July 2020 - 12:18 AM

How about using dual MOD 3's in binocular telescopes such as

 

https://www.telescop...cular telescope

 

is that a pursuit that will deliver impressive results?



#9 jdbastro

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Posted 02 July 2020 - 12:54 AM

...

 

Now two or three years ago (time flies!) there was a small lot of PVS-7s sold with filmless white phosphor tubes. 

...

Only FIVE of these tubes were made for Glynn Sziraki back in the spring of 2017.

 

You are indeed fortunate to have acquired one of these 10130 unfilmed WP tubes.

 

I have 6 PVS-7s.  One of them has one of these unfilmed tubes, and it is indeed my all time favorite PVS-7 to look thru.

 

Enjoy!



#10 jdbastro

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Posted 02 July 2020 - 12:56 AM

How about using dual MOD 3's in binocular telescopes such as

 

https://www.telescop...cular telescope

 

is that a pursuit that will deliver impressive results?

Definitely will produce impressive results if you can get the image tubes to reach focus.  Chances are that the image plane produced by each scope is buried deep inside the eyepiece holders.


Edited by jdbastro, 02 July 2020 - 12:57 AM.


#11 joelin

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Posted 02 July 2020 - 01:45 AM

Only FIVE of these tubes were made for Glynn Sziraki back in the spring of 2017.

 

You are indeed fortunate to have acquired one of these 10130 unfilmed WP tubes.

 

I have 6 PVS-7s.  One of them has one of these unfilmed tubes, and it is indeed my all time favorite PVS-7 to look thru.

 

Enjoy!

How do they compare with your experience of a high performing monocular? Did you miss the adjustable gain?



#12 jdbastro

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Posted 02 July 2020 - 01:57 AM

How do they compare with your experience of a high performing monocular? Did you miss the adjustable gain?

My unfilmed PVS-7 rivals my best monoculars which are all fixed gain units (unfilmed tubes).

 

My only experience with manual gain is on Gen 3 25mm tubes in housings like a TVS-5 and Star-Tron LR300 and LR170 configurations.

 

So, not enough experience with manual gain to miss it.



#13 Joko

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Posted 02 July 2020 - 01:59 AM

In Europe there are no issue to get high specs tubes for bino equivalent to mono.

I did many tests in June using 2 tubes (2 OVNI-M in a binoviewer) and 1 tube (PVS-7).

Here are my results :

 - for astronomy use in a telescope, the view was much better in a PVS-7 than in 2 OVNI-M. The reason was explained by Eddgie : "To reach focus without using a Barlow or GPC is very difficult" So you need a Barlow, meaning you start observing at high power while you can observe at low power with a PVS-7 (and also use it in afocal). So i would suggest monocoular observation with 1 OVNI-M than binocular observation with 2 OVNI-M. 

 - for astronomy use in a bino telescope the view is better with 2 OVNI-M than a single telescope (with the same aperture than the bino telescope) with a PVS-7. More light and less scintillation.

 - for terrestrial use, 2 OVNI-M binocular are much more impressive than a PVS-7. 3D views are breathtaking ! More light and field view is larger.

 

Also i have to mention that OVNI-M has manual gain control which is great while PVS-7 don't have it.

Here are my feelings for 2 eyes observations with 1 or 2 tubes.


Edited by Joko, 02 July 2020 - 02:05 AM.

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#14 joelin

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Posted 02 July 2020 - 02:33 AM

In Europe there are no issue to get high specs tubes for bino equivalent to mono.

I did many tests in June using 2 tubes (2 OVNI-M in a binoviewer) and 1 tube (PVS-7).

Here are my results :

 - for astronomy use in a telescope, the view was much better in a PVS-7 than in 2 OVNI-M. The reason was explained by Eddgie : "To reach focus without using a Barlow or GPC is very difficult" So you need a Barlow, meaning you start observing at high power while you can observe at low power with a PVS-7 (and also use it in afocal). So i would suggest monocoular observation with 1 OVNI-M than binocular observation with 2 OVNI-M. 

 - for astronomy use in a bino telescope the view is better with 2 OVNI-M than a single telescope (with the same aperture than the bino telescope) with a PVS-7. More light and less scintillation.

 - for terrestrial use, 2 OVNI-M binocular are much more impressive than a PVS-7. 3D views are breathtaking ! More light and field view is larger.

 

Also i have to mention that OVNI-M has manual gain control which is great while PVS-7 don't have it.

Here are my feelings for 2 eyes observations with 1 or 2 tubes.

 

interesting comparisons

how about a single NVD in a 150mm f/4 newt vs two NVD in a APM 100mm binocular telescope (550mm focal length) ?


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#15 Gavster

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Posted 02 July 2020 - 03:52 AM

How about using dual MOD 3's in binocular telescopes such as

 

https://www.telescop...cular telescope

 

is that a pursuit that will deliver impressive results?

Yes it is!

See this thread

https://www.cloudyni...sion-binoscope/

It’s even better with the new 67mm Televue adapter in each 55mm plossl...


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#16 Eddgie

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Posted 02 July 2020 - 06:58 AM

How about using dual MOD 3's in binocular telescopes such as

 

https://www.telescop...cular telescope

 

is that a pursuit that will deliver impressive results?

I would think it would.  I have not used a binocular like this, but I have used the 50mm CCD Guider binocular and it worked quite well.  A true binocular is going to eliminate the issue of beam splitter loss and the heavy field illumination falloff that is present when you use a monocular with a binoviewer.  The very long light path of the binoviewer is just too severe an issue.  It reduces the fully illuminated field to tiny diameters and limits the useful focal ration to relatively slow speeds.

 

A true binocular will not have these issues.  There are a few people on CN using binoculars afocally and this is the only way to do it with all of the binoculars I know of on the market. I have not seen a binocular out there that would reach focus using a pair of Mod 3s at prime focus.  But afocally, you can make any binocular work. 



#17 joelin

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Posted 02 July 2020 - 11:03 AM

Anywhere I can find a review of the 50mm guider bino and how it was built?

#18 GrahamDFyffe

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Posted 02 July 2020 - 12:01 PM

How about using dual MOD 3's in binocular telescopes such as

 

https://www.telescop...cular telescope

 

is that a pursuit that will deliver impressive results?

I have an Oberwerk BT100XL binocular telescope. I tried the Mod 3 in it but it does not come to focus at prime.


Edited by GrahamDFyffe, 02 July 2020 - 12:04 PM.

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#19 joelin

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Posted 02 July 2020 - 12:20 PM

I see.
Is there an easy way to build a binoscope using say any pair of refractors?


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#20 Eddgie

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Posted 02 July 2020 - 02:23 PM

I see.
Is there an easy way to build a binoscope using say any pair of refractors?


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Building a binocular telescope is not an easy proposition. 

The easiest way to do it yourself is very expensive, but that would be to use the EMS Binoback system.  For the longest time they did not have a direct competitor but there is now another company that sells a similar system.

 

http://ems-bino.com/...t-line-english/

Even here though, it is almost always necessary to modify the telescopes by cutting down the tubes. 

 

Now if you have some fabrication skills, there are other ways to do it.  The Binocular forum has some interesting home made binocular telescopes. 

 

I have seen a bunch of people say that they were going to build large binoculars, but few do.

 

Again, I think the Matsumoto setup is probably the most elegant, and as I mentioned, they do now have a competitor with slightly lower prices but I cannot remember who they are. 


Edited by Eddgie, 02 July 2020 - 02:24 PM.


#21 Solar storm

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Posted 02 July 2020 - 07:42 PM

I absolutely love mine.  My Green one has a gain knob I installed and is great, but my white phosphorus one is magical.



#22 joelin

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Posted 02 July 2020 - 07:57 PM

How do you install a gain knob on a PVS7

#23 pwang99

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Posted 02 July 2020 - 11:12 PM

Congrats on your new toy, Ed! :-)

 

I ended up selling my WP PVS-7 (maybe we should call this rare run "Glynn's Quintet") earlier this year... I was thinking maybe I'll get a second Mod-3 later in the year so I can go full bino.



#24 joelin

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Posted 03 July 2020 - 12:42 AM

Building a binocular telescope is not an easy proposition. 

The easiest way to do it yourself is very expensive, but that would be to use the EMS Binoback system.  For the longest time they did not have a direct competitor but there is now another company that sells a similar system.

 

http://ems-bino.com/...t-line-english/

Even here though, it is almost always necessary to modify the telescopes by cutting down the tubes. 

 

Now if you have some fabrication skills, there are other ways to do it.  The Binocular forum has some interesting home made binocular telescopes. 

 

I have seen a bunch of people say that they were going to build large binoculars, but few do.

 

Again, I think the Matsumoto setup is probably the most elegant, and as I mentioned, they do now have a competitor with slightly lower prices but I cannot remember who they are. 

What are all the c mount lenses that will allow mod 3 binocular operation and most users to have a comfortable IPD? I think I’ve seen the 50mms work but how about higher focal lengths?


Edited by joelin, 03 July 2020 - 12:42 AM.


#25 jdbastro

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Posted 03 July 2020 - 01:17 AM

What are all the c mount lenses that will allow mod 3 binocular operation and most users to have a comfortable IPD? I think I’ve seen the 50mms work but how about higher focal lengths?

75mm f1.4 lenses should work for most people.  Beyond that focal length, you have to go with a slower f ratio unless you have Humpty Dumpty wide eyes.  I've tried up to 200mm f4.  That gets difficult to hand hold and collimation becomes somewhat of an issue.




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