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PVS-7 w/ 2" reducer? Is it your diagonal holding you back?

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#51 cnoct

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Posted 02 December 2015 - 12:16 AM

NV bino-viewers will get spanked, seriously switch whipped, by a single tube bi-ocular PVS-7 type NV system time and time again. 

 

Each image intensifier in dual tube NV bino-viewer receives a mere 50% of the available photon data collected by the telescope/objective lens, whereas the single image intensifier in a single tubed bi-ocular NV viewer (PVS-7) receives 100% of the available photon data stream. 

 

Bino-viewer halves the available photon data to each image intensifier i.e. each intensifier receives half the input data to convert and multiply.

 

Bi-ocular viewer delivers 100% of the available photon data to the single image intensifier and then divides the multiplied output data between each eye.

 

Obviously image intensifiers lack the summing and processing of the human eye so the system that delivers the most photon data to the image intensifier/s wins every time, in the case of bino-viewer vs bi-ocular, the bi-ocular system wins with a knock out in the first round. 

 

Nothing personal against NV bino-viewers, it's just the physics of it. 

 

NV bino-viewers just don't add em up!



#52 Vondragonnoggin

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Posted 02 December 2015 - 12:31 AM

I think if someone is well aware of what binoviewers do with splitting the light and counts that dual tube systems on a scope of a particular aperture will be like getting half the aperture to each eye x1.41 to account for binocular summation, then using dual tubes in a BV should deliver what they expect. 

 

For instance a 120ST with a BV would deliver the equivalent of 84mm aperture to each eye after summation is accounted for and if a person's summation ability is in a normal range. Although the tube is not benefitting from summation gains so 60mm apertures worth of photons to each tube.

 

Which would be awful close to my 70mm binocular telescope but actually come to focus.

 

I am just wanting to find out if it appears as though you are looking through two tubes with clean views of the monocular vs the views through a PVS-7. I can drop my PVS-7 into my 72mm scope to compare to the 120ST with BV. They should have similar light delivery.

 

Each tube should still get the resolution benefit of the larger objective as well vs putting a monocular in a 60mm scope.


Edited by Vondragonnoggin, 02 December 2015 - 12:55 AM.


#53 Vondragonnoggin

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Posted 02 December 2015 - 12:39 AM

Where my 1.41x number comes from in regards to binocular summation 

 

http://www.cloudynig...sion-summation/

 

and the specs of my PVS-7 tube should theoretically deliver some views along with binocular summation, that spank the monocular, but they don't. The monocular has the cleaner appearance.

 

I am looking to test that cleaner appearance with both eyes in play even though I inow each tube will get less photons than the PVS-7 tube by the single aperture. I appreciate that the info was added though for those that might not be aware that a BV's beam splitter actually halves the light of the scope and delivers each half to right and left eyes, and that the tube now only sees half the photons the PVS-7 sees

 

  :)

 

So for me, the closest comparison would be 120ST with BV and two monoculars to AT72ED with PVS-7 or 120ST with PVS-7 to AR152 with BV and two monoculars.


Edited by Vondragonnoggin, 02 December 2015 - 12:59 AM.


#54 Vondragonnoggin

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Posted 02 December 2015 - 01:24 AM

Something I haven't touched upon before in my postings is the performance of the three bioculars I have compared to each other. 

 

The cleanest view biocular I have at the moment is the NiTec with single lens biocular that is a good 3/4" smaller in size than the PVS-4 single lens biocular. Both of these are 25mm tube devices and do not deliver the high performance of the 18mm tube devices. They are close. They are also very clean in appearance. The big biocular on the PVS-4 does have barrel distortion though. The view appears curved although it is all in focus at the same time unlike field curvature. The smaller NiTec does not exhibit this barrel distortion. Both have cleaner views similar to my 18mm monoculars in appearance. The other biocular is my PVS-7 and it does great, but the clean view of the monoculars and 25mm tube devices is noticeably cleaner than the PVS-7. The same objects are present, but the aesthetics of the view is better in the monoculars than the PVS-7 in my opinion.

 

I am looking for that with two monoculars in a BV, even if less light is delivered.

 

Also if this wasn't a noticeable difference in clean, I would prefer my PVS-7 to use almost all the time, but I don't. Many times I reach for one of the monoculars because of the cleaner view and being able to distinguish finer contrast in the monocular because of less noise present or resolution of the simpler photon to eye train of parts involved. Sometimes it even trumps the comfort of two eyed viewing incidentally which is delivered best by the largest biocular with the barrel distortion. One big ocular for both eyes and being able to sit your eyes a couple inches from a 4" window to space is worth the slightly curved view the barrel distortion causes for the viewing comfort alone.

 

Also to give an idea of PVS-7 use over almost two years - I only recently changed batteries for the first time when swapping out for a higher spec tube. The old batteries still had charge.


Edited by Vondragonnoggin, 02 December 2015 - 01:39 AM.


#55 Vondragonnoggin

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Posted 02 December 2015 - 01:52 AM

To put the PVS-7 comparison in a more simple manner than all that spewing of words I just did - knowing what I know now after using these for the amount of time I have, and given the background of owning 4 regular binoculars and two binocular telescopes with no less than ten standard eyepiece pairs, and being a bino enthusiast, if given the choice of PVS-7 or NVD Micro with similar spec tubes, I would prefer the Micro, even though it is a monocular.

 

Just my own personal preference here speaking. That is not to say I don't like my PVS-7 and get spectacular views from it. All the devices I have are preferred tenfold over standard eyepieces on DSO's

 

My ideal device would be a high spec Micro with variable gain, that had a very large single biocular lens with no barrel distortion. Unfortunately, that does not exist in ready to buy status.

 

Wow - almost forgot to put avery important point to all this - This preference is in regards to narrowband Ha viewing only. When using less aggressive filtering like a longpass filter for picking out clusters and Milky Way sweeping, I love the PVS-7 views and prefer it over the monoculars. The issue of clean views being better in monoculars is all narrowband work related.

 

:blink:  :silly:  :looney:

 

Sorry for the frantic posting, but thought an explanation to my theoretical musings on device use was in order.


Edited by Vondragonnoggin, 02 December 2015 - 02:03 AM.


#56 cnoct

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Posted 02 December 2015 - 02:17 AM

The bifurcating optical train in the PVS-7's prevent that NV system from ever producing views equal to those of a straight through system like the Micro or PVS4.

There's no question as to whether or not NV bino-viewing is viable, it is to varying degrees of success. Straight through systems will always have higher MTF.

Whether you NV bino-view, NV bi-ocular view, NV Mono-view or use a hybrid of those I'm all for it.

The experience is what counts and I'm all in for hearing about your experience with NV bino-viewing.

BTW: The ocular on the Micro features an eyepiece cell that is offset in the cell sleeve. You'll need to rotate the monoculars until the images are collimated. See included picture below.

 

Offset%20Ocular%20Cell_zpscx1hse5v.jpg



#57 Vondragonnoggin

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Posted 02 December 2015 - 04:16 AM

A pic is worth a thousand words sometimes. Thanks for that one. I could see some head scratching not knowing that little, but important, piece of info.

 

:)



#58 Eddgie

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Posted 02 December 2015 - 09:08 AM

 

 

Wow - almost forgot to put avery important point to all this - This preference is in regards to narrowband Ha viewing only. When using less aggressive filtering like a longpass filter for picking out clusters and Milky Way sweeping, I love the PVS-7 views and prefer it over the monoculars. The issue of clean views being better in monoculars is all narrowband work related.

 

 

 

Ha, this mirrors my preference almost exactly!

 

I tend to use the Micro with a SLR lens and a filter for nebula (and also because I think the ergonomics of the Micro are better when used with a heavy SLR lens).

 

For low power sweeping and low power rich fields, I greatly prefer the PVS-7 and that is why I have been trying to be patient with my hopes of getting a ULT PVS-7.  

 

Anyway, I tend to use the Micro for Nebula and heavy zooms, and have pretty much gone to the PVS-7 for Unity and 3x with the clipon.

 

For telescope use, I also prefer the PVS-7, and I just keep the Micro on standby with the H-a filter in it for nebula viewing.  That way, if I go to a nebula, I can just swap out.

 

For "Grab and go" and dinner parties, it is the Micro and 3x afocal.  Just so small and light and anyone can use it and go "Wow!"   



#59 outofsight

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Posted 02 December 2015 - 01:43 PM

Thanks very much for the input cnoct, although I'd still like to see it for myself. But it really helps tamp down the wondering process, wondering if I should spend about $6k on two NVD Micro.

 

And it makes me happy about my PVS-7s, of which I'm about to finally finish a new one today with all new parts and a nice-new-clean tube. Then I can a/b compare them and set up two scopes or just leave one at 1x or whatever. Should be having fun by this weekend if the clouds will ever truly go away.

 

By the way, that picture of Eta Carinae Nebula is just plain nice. From the black and white to the lightly scattered clouds it simply evokes a nice night. A few clouds are nice, they give perspective, they generate the feel of the earth to the stars: most excellent.


Edited by outofsight, 02 December 2015 - 01:46 PM.


#60 Vondragonnoggin

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Posted 02 December 2015 - 02:49 PM

I wouldn't rush out to buy another monocular either. I can try it on the cheap without even having to get another micro housing. I can simply use the two monoculars I already own. They are almost the same length with nosepiece on. The slight difference won't impede testing. 

 

I would caution anyone against rushing out to buy two micro's after reading a few threads. I would encourage putting one together if it is a financial possibility though. Even my Omni IV MX10160 tube in the litton housing, which is around 21 S/N and 64 lp/mm and higher EBI than new 27.8 S/N, 72 lp/mm tube in the PVS-7, gives cleaner Ha narrowband performance.

 

There are used tubes on ebay and you can buy just the micro housing.

 

I mean having two Ultra Micros hand selected would be neat, but not necessary to enjoy views. The only high spec tubes I have were recently aquired. I viewed with just regular old good tubes for almost two years. I am thankful for the experience to see what the differences are, but I'm in no hurry to buy anymore high spec tubes. I'll still make use of the older ones.

 

Even if I was somehow given the choice to trade my two PVS-4's plus two older tubes for two brand new Ultra Micro's, I wouldn't do it. These different devices offer unique views.

 

Sometimes its not all about the best device with highest performance.

 

The forum is a good place to gather info and get ideas about whats out there. I would be more inclined at this point with current devices, to put together the DIY p8079hp cascade tube monocular just to experience it, than buy another full price micro. I could get more experience and a unique view that way.


Edited by Vondragonnoggin, 02 December 2015 - 03:18 PM.


#61 Vondragonnoggin

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Posted 21 December 2015 - 10:44 AM

I have not bothered to change my 120ST linear bearing adapter yet, but will do so this week. I have a little more motivation now. Last night I tried the WO binoviewers with my two mx10160 tube monoculars in my AT72ED scope. Two different housings but very similar in size. I needed a 2x barlow to get them to come to focus in the AT72ED.

 

I was doing A/B comparisons with monoculars and my 3nm 2" filter in the diagonal. Then I tried the WO binoviewers. I put my 2" 2x Telecentric Barlow in and the WO loaded up with monoculars. I then did A/B comparison to my PVS-7. 

 

The AT72ED is 70mm x .5 for the WO beamsplitter giving the equivalent light of 35mm objectives to each monocular at a whopping F/12 light cone. The PVS-7 getting the full 70mm but at F/12 light cone also.

 

What I found -

 

Expected:

views were dimmer in the binoviewer

noise was high

stack of equipment higher in the diagonal

 

Unexpected:

view was more 3D appearing by a good margin

view, even though dimmer and more scintillations, was clearer in pinpoint stars and definition in the WO

 

Neither system was performing like I wanted with the 2x Barlow added. If I did not have to use a 2x Barlow to come to focus, I think the less scintillations would give the edge in clarity to the BV with monoculars. Even with photon input halved by beamsplitter.

 

Looks promising to use on the much shortened 120ST once new adapter is on. This would be very promising in a shortened scope requiring no OCS that had native focal length of F/5 or less. It would also be more ideal with matched tubes and indentical housings, but I only had to pull up my Litton M942 1/8" in the ocular holder to match focus points of the Micro. Both monoculars have generous eye relief, so this was not a problem to view with glasses on and still have plenty of wiggle room between top of monocular and eyeglasses.

 

Will update more when I get shorter adapter put on the 120ST.

 

Only one nebula target - Orion. Also looked at little beehive cluster. It was a fairly brief comparison. Maybe 30 min comparing between two devices. Several swaps to A/B it a few times.

 

Rather surprising on a few things.


Edited by Vondragonnoggin, 21 December 2015 - 10:48 AM.


#62 Vondragonnoggin

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Posted 21 December 2015 - 10:53 AM

Oh and like a big dummy, after I got done A/B'ing the two monoculars and confirming the Micro had the definite cleaner view, I totally forgot to put the Micro to my least dominant eye and the Litton to my dominant eye to balance things out like I had planned to do for using the two in a BV.

 

I Was too excited trying out the BV's and A/B'ing to the PVS-7 to think about it at the time, but next experiment I will do as planned and try to match tubes bettter by putting stronger cleaner tube to weak eye and noisier, older tube to dominant eye.

 

:)


Edited by Vondragonnoggin, 21 December 2015 - 10:55 AM.


#63 outofsight

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Posted 21 December 2015 - 01:31 PM

VDN, thanks for update #61. This is all good stuff. Glad to hear there was some 3D effect. Might be a very long term project for me.



#64 cnoct

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Posted 23 December 2015 - 03:20 AM

Solid reporting there VDN!

The uncorrelated noise probably gives the 3D effect a bit of a boast, what do you think?

Seems the star shapes in the BV reveal just how much the optics of the PVS7 degrade the image.

Don't you wish these were a bit more accessible: Fraser NV Eyepiece for Gyro Stabilized Binoculars



#65 Vondragonnoggin

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Posted 23 December 2015 - 04:58 AM

Oh wow. Considering they have to attach to the Stedi-eye gyro stabilized binos

 

http://www.bhphotovi...Stabilized.html

 

at $6400 also and you need two of those that you linked to at $5800 each, quite inaccessible to me for nearly $20,000 for image stabilized 12x binos. Plus you need to be a member of law enforcement or military.

 

But just imagine handheld gyro stabilized 12x night vision true binos.......would be completely awesome.

 

cnoct - to your statement about uncorrelated noise adding to the 3D effect - yes, I definitely think that was a contributor. 

 

My experiments with BV's need some refinement to get down to F/5 and a better representation of signal without extra scintillations happening from the 2x barlow. Really is not ideal to view beam split signals at double the focal length, but yes, the amount the bifurcated optics in the PVS-7 degrade the image is obvious. 

 

True binoscope use with dual monoculars would be much better. I have still not tried to get focus in my APM 100ED Semi-apo binocular telescope. I don't have much hope for the helical focusers though after not coming close in the 70mm binocular telescope, but maybe afocal digiscope style with a pair of 28mm RKE's would yield some great views. Just would be an awkward setup trying to clamp those to the RKE's. Binocular telescopes are not the same as binoscopes either. Very close, but BT's really are a low power instrument too. My own two BT's with standard eyepieces only truly good at about 16x - 50x max because of the prisms used and glass types for the twin scopes. 

 

A borg binoscope with the 89ED telescopes used for the twin tubes and those nice EMS binobacks stuffed with two NVD Micros put in twin feathertouch focusers on the 89ED scopes would knock the socks off me for sure. It is a lightweight true binoscope too at around 16lbs.

 

http://www.sciencece.../bino/index.htm

 

They don't actually list the 89ED (Nozomi) there but that is the biggest available now I believe.

 

Some more pics - https://digiborg.wor...aok-platform-1/

 

Price list - http://www.sciencece...prices/bino.htm

 

$5525 for 2" feathertouch focusers and 2" binobacks

 

But there too you are looking at nearly $20,000 if full price paid for everything.

 

Aahhh - one can dream about it though. It's not like I'm stuck with bad views in the meantime. I already spoil myself with such magnificent views with current equipment.

 

Hey, just realized with two monoculars already, really only about $6000 away from that dream!

 

:)

 


Edited by Vondragonnoggin, 23 December 2015 - 05:46 AM.


#66 cnoct

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Posted 26 December 2015 - 08:03 AM

Those articulating erector gives the BORG Bino that submariner look, pretty neat!
 
I'm looking forward to your NV viewing report with them :D . A report on the Fraser Stedi-Eyes would be cool as well :D  :D .  
Did you get your adapter so you could reach focus without the Barlow?
 
As far as afocal mounting of dual nv units onto binoculars, I give it a big :waytogo: .
 
I've had great success doing this and found it to be one of the cheapest ways to add magnification. Though it  certainly isn't the best method if the goal is to maximize efficiency it is rather simple and effective. Since most folks have a pair of binoculars lying about this adaptation makes great use of existing equipment, always a bonus.
 
A good friend uses Fujinon Stabilized 14x40 Binoculars with two PVS-14's coupled to the oculars with day scope adapters, unreal setup.
 
I use this old MK 32 from the 1940's that that work rather well:
 
Econo%20NV%20Binoculars_zpsqjsmcgit.jpg

#67 Vondragonnoggin

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Posted 26 December 2015 - 01:25 PM

Wow. That looks awesome. You just pulled a rabbit out of the hat on that one.   :)

 

I need to work on my NV tricks better.   :lol:

 

Great idea though. I have some better food for thought with that picture.



#68 The Ardent

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Posted 26 December 2015 - 03:10 PM

True binocular viewing! 



#69 Vondragonnoggin

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Posted 27 December 2015 - 04:25 PM

TS Monorail does not fit scopestuff GSO linear bearing adapter. 

 

TS Monorail has its own flange different than GSO's to fit 96mm ID of Skywatcher factory flange. 

 

Have to rethink this one......

 

 

Not done yet by a long shot though.



#70 Vondragonnoggin

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Posted 29 December 2015 - 03:20 AM

Cnoct - is that some clip on scope mounting system adapter you are using to couple the pvs-14's to the eyepieces on the binos?



#71 cnoct

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Posted 29 December 2015 - 12:39 PM

Nothing fancier than a pair of $2 rubber pvc pipe couplers, works great, real snug fit! 

 

One of the best afocal coupling systems is the MonoLocpremium stuff right there. 

 

 

 

 




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