26 replies to this topic

[Gavster]

I’d had a slightly frustrating observing session this evening, so I decided to finish up with some relaxing 1x night vision viewing of Orion.

My London back garden has an SQM reading of 18.5 so I was quite pleased to be able to see the top half of Barnard’s Loop. I have seen it before from London but this evening is stood out a bit more.

I then decided to compare my two pvs-14 night vision monoculars. With various adapters I have I’m able to attach both 1.25 and 2 inch filters to the front of my monoculars - as I have two ha filters of the same type but different size I could therefore do a direct comparison.

The comparison was interesting and as previous, the Harder Gen 3 beat the Photonis 4g.

However, I recalled Eddgie suggesting I try my monoculars at 1x binocular style ie one to each eye. So I decided to give it a go and the impact was pretty amazing. Suddenly not only could I see the top half significantly clearer but I also could see the entire loop stretch round Orion to Rigel, much like the views I got at my dark SQM 21 site a month ago (see image below)

 

Two eyes are definitely better than 1 in this case and I found it easy to merge the views at 1x. It was a great way to finish the session!

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[BJS]

That is a very nice image!  Really shows what you can see with a halpha filter.

[TOMDEY]

Nice! I use two, one to each eye. At 1x, the merging is automatic, provided you got your pupils on each and they are even roughly pointed in the same direction. For 3x, I attach them to the Howie Glatter plate, built for two Coronado PSTs. I can accomplish that feat ONLY because my pupils are unusually far apart (71mm)... otherwise they would bump into each other.

 

OK, so looking at your picture there, I can almost convince myself that the Horsehead is (barely) visible as a little notch in the H-alpha there. I know I can see that, rather clearly, real time, holding one in each hand. Can you see that?

 

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[Gavster]

I’m not convinced I saw the notch at 1x from London but to be honest it was getting late and I was focussing on Barnard’s Loop and the Angelfish nebula (which I also managed to see - first time in London for this object with me).

[PEterW]

This is getting expensive!! So you notice any difference in the tube performances? I guess you need some form of adjustable mount to hold them aligned?

Peter

[Gavster]

This is getting expensive!! So you notice any difference in the tube performances? I guess you need some form of adjustable mount to hold them aligned?

Peter

Yes there is a difference in tube performance but I found that my eyes compensated fine. I just held them to my eyes one in each hand no mount - worked surprisingly well.

[Gavster]

I’ve discovered and got hold of a nice light bracket that can fix my two pvs-14 monoculars together as a 1x night vision binocular.

Its cloudy here so I could only do terrestrial testing but it works really well. The clamp screws into the tripod screw on each monocular and is non-marring. Collimation at 1x is automatic.

There is a lovely 3D effect terrestrially that you don’t get with just one. And detail is definitely easier to pick out with two eyes being used with reduced scintillation. I’m very optimistic about putting two ha filters on these and going out for a super wide field visual scan. 1x night vision observing is great fun!

 

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Edited by Gavster, 18 January 2019 - 06:42 AM.

[AllanDystrup]

Amazing

[Luis Serrano]

Looks great! The truth is that 1x night vision observing is really addictive (...even more if you live in a light contaminated place). Lately, I think that 95% of my observations are at 1x :-). 

[Eddgie]

Looks great! The truth is that 1x night vision observing is really addictive (...even more if you live in a light contaminated place). Lately, I think that 95% of my observations are at 1x :-). 

Yes, binocular is very cool to use.

 

Like you, a great deal of my own observing is at 1x, 3x, and 6x.  It is just the ease of it.  Just grab your device an a lens and step out and observe.   I have not yet gotten tired of seeing the sky at low power, and the summer Milky Way is different at all of these powers, with and without filters.

 

That being said, a binocular is a tough value proposition for something that can really only be used at very low powers.  with the PVS-14, the limit is really 3x (assuming that people have a wide enough IPD to accommodate the size of the 3x afocal lenses).  It is a pricey expenditure for low power work.   

 

For people with a Mod 3, it is a bit better because they can use the CCD Finders, but this is not the most comfortable rig to hold and collimation is a problem at this kind of power.  Alignment of the bridge has to be precise.

 

 

It is amazing though but again, it is twice the fun at 3 times the price.  

[Eddgie]

And on the CCD finders, I had serious problems with alignment, but now that I have a 3D printer, I may print a couple of brackets that could slip over the CCD finders to hold them in alignment.  The Mod 3 bridge has some slop in it and even at 3x, it can be a bit tedious to hold the lenses in collimation.  Guess I should make a bracket for the 3x lenses too. A simple one would have fixed IPD, but the exit pupil of the eyepiece on monocular is big enough that IPD does not have to be exact and frankly, if I have friends, I prefer that they use a monocular.  Just like with a binoviewer, it is kind of fidgety to get it set up from one obsever to the next.   Easy to pass around when they only have to focus one eyepiece. 

[Gavster]

And on the CCD finders, I had serious problems with alignment, but now that I have a 3D printer, I may print a couple of brackets that could slip over the CCD finders to hold them in alignment.  The Mod 3 bridge has some slop in it and even at 3x, it can be a bit tedious to hold the lenses in collimation.  Guess I should make a bracket for the 3x lenses too. A simple one would have fixed IPD, but the exit pupil of the eyepiece on monocular is big enough that IPD does not have to be exact and frankly, if I have friends, I prefer that they use a monocular.  Just like with a binoviewer, it is kind of fidgety to get it set up from one obsever to the next.   Easy to pass around when they only have to focus one eyepiece. 

Eddgie, how much difference in the views do you notice between using monoculars vs binoculars?

The reason I ask is that I’ve just had a decent 45 minute session with my NV binoculars and I’m continuing to notice how much better the binocular views are compared with monocular.

I’ve been observing in my London back garden where the skies are sqm 18 and the neighbours have lights on and yet I’m seeing the whole of Barnard’s Loop very clearly. The Angelfish is also very distinct. With just the monoculars I only get the top bit of Barnard’s and the Angelfish is not clear at all.

Swapping to 685 filters I also definitely able to observe fainter stars than with my monocular.

I got a dark sky trip coming up soon and I really can’t wait to use these there for the first time.

Edited by Gavster, 25 January 2019 - 07:20 PM.

[Eddgie]

There is no doubt that the binocular view is better than a monocular view.

 

There are reasons for this.  The first is simply that using two eyes increases your visual acuity.  This is why I used to use binoviewers for planetary work.

 

The second is because of binocular views benefit from "binocular summation".   This is analogous to stacking photos.  While the view in each binocular is no brighter than a single monocular, the brain stacks these images and the result is that an image will appear about 30% brighter. Now in a traditional binoviewer, the signal to each eyepiece is cut in half from the original brightness, but the summation brings the brightness up to about 70% or so of what the aperture would normally provide (rather than the 50% each eyepiece gets). 

 

Last, the noise coming from each tube is once again, kind of canceled out one against the other so that the net result is that the signal to noise ratio is improved by about 30%.   This means that if you have two tubes that have an SN of 30 each, the effective signal to noise ratio will be about 30% greater, or equivalent to a SN of about 40 (at least this is the way I understand it, but I could wrong).  Now as I understand it, you get this in the binocular because the noise patterns in each tube will never be the same so as each eye gets the signal, the brain is integrating the best of each image.  Now I don't think the PVS-7 does this because each eye sees an identical image (both are looking at the same tube display).  The PVS-7 gets summation (for the brightness, though this is arbitrary because the initial brightness is set by the automatic brightness control in the PVS-7 tube) but since both eyes see the exact same noise pattern, you would not get the SN boost using a PVS-7.  At least this is the way I think it works, but I could be wrong.  I know that the true binocular seems much less noisy than a single tube, but my PVS-7s don't seem to show this difference, though I do think that if I use one eye at the PVS-7 and then open both eyes, the view is better (see first and second reason) but I do not notice an improvement in SN the way I do with the true binocular.

Edited by Eddgie, 25 January 2019 - 07:24 PM.

[Eddgie]

You can also do things like put different filters on the binocular modules.  For example, you can put an H-a on one side and no filter on the other.  You have to turn the non-filtered gain down quite low to be able to merge the images, but now you see stars and nebula.  

 

I have used a 12nm on one side and a 7nm on the other and this really opens up the brightness of nebula at the edges of the field.  The narrower band filters have that band shift.  You won't see as much nebula as if you used two 7nm filters, but you don't have to pan around as much.  I think it is better to run the same filter on each side, but I have played around with different combinations.

 

There are a lot of benefits to using the full binocular, but as I say, it is extra fun, but at more than twice the price.

[Gavster]

I’ve just received another 3x lens today to make this setup. Completely cloudy obviously but I’ve done a quick test outside. Collimation was relatively straightforward (but the extra weight of the lens means you have to hold them a bit more firmly) and my ipd was enough with 2mm to spare. 

Looking forward to when the skies clear...

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[Luis Serrano]

Lovely setup! 

[SiriusLooker]

May I ask (how) or exactly what was use to get that stunning image of Orion Constellation.?

 I have a PVS-7D  with both 7nm / 12nm ha filters(1-1/4in), and I dont get that kind of detail. Is this video image (enhanced)?   I can see the barnard loop and about half way to almost rigel, and I am in excell dark skies of Arizona, 6,7mag... And also see the Angelfish, but not that structural detail like in pic

May I ask what is the intensifier being used  I have a standard 10130D, do i need to upgrade to get better results?  Or better lens.. I have the standard lens 1x that comes with it, Also the 3x / 5x military grade lens too.  

[SiriusLooker]

Note.. I know you are using a true-bino setup, however that image is obviously only shot thru (one) lens, and yet the detail of nebulas are quite impressive. Are the PVS 14 that much better for seeing structure in clouds versus PVS 7, even in the mono version?

I am sorry for long delay on this reply, but I just caught this nice topic from you.

[Gavster]

May I ask (how) or exactly what was use to get that stunning image of Orion Constellation.?

 I have a PVS-7D  with both 7nm / 12nm ha filters(1-1/4in), and I dont get that kind of detail. Is this video image (enhanced)?   I can see the barnard loop and about half way to almost rigel, and I am in excell dark skies of Arizona, 6,7mag... And also see the Angelfish, but not that structural detail like in pic

May I ask what is the intensifier being used  I have a standard 10130D, do i need to upgrade to get better results?  Or better lens.. I have the standard lens 1x that comes with it, Also the 3x / 5x military grade lens too.  

This was a phone image of around 10 seconds exposure through my pvs-14 with a 5nm ha filter with no post processing. The actual eyepiece views were very very similar. It was from a dark site sqm 21+. 
As you are observing from a dark site, I’d suggest that the reason for the lack of detail is three fold - pvs-14 does give clearer views than the pvs-7, my tube is a very good spec gen 3 white phosphor tube and the filter I was using was a top quality 5nm filter that gives significantly better contrast than a 7 or 12nm filter. 
 

Edited by Gavster, 10 October 2019 - 11:22 PM.

[Eddgie]

Note.. I know you are using a true-bino setup, however that image is obviously only shot thru (one) lens, and yet the detail of nebulas are quite impressive. Are the PVS 14 that much better for seeing structure in clouds versus PVS 7, even in the mono version?

I am sorry for long delay on this reply, but I just caught this nice topic from you.

Most of the difference is probably in the tubes.   It is very difficult to find a PVS-7 tube (10130 D/UV) that has the same performance of the top end MX11769 tubes that most people using a Mod 3 or PVS-14 are using.

 

In fact, it is hard to find a PVS-7 tube that is as good as the F9800VG which can be pretty close to the MX11769.

 

I have owned I think six or seven PVS-7 tubes (in search of the "best" one), including four "Omni VII" tubes, and none of them have performed even close to my F9800 (which has the same specs as the 10160C/AVS-6 which is an Omni VI/Omni VII spec and is the same quality that is used in military aviation binoculars) and while all were capable of showing a lot of things, none were close to any of these monocular tubes in performance. The view in the PVS-7 tubes was always nosier and the EBI was always much higher than with my MX11769 tubes (though some had less EBI than my F9800 spec tube). 

 

Now there have been some PVS-7 filmless tubes in white phosphor made in recent years, and I have had the opportunity to view with one of these, and the result was quite good! Not quite as sharp as a good monocular (some chromatic aberration) but far better than even the very best of the "Omni VII" PVS-7s I have used.  No comparison at all.   This tubes had high SN (around 30 or 31 as I recall) and appeared to have very low EBI, though I think when I got to use it, it was a cooler night. 

 

So, I have never seen a standard PVS-7 Omni VII tube that could perform as well as the better monocular tubes.

 

Would it be worth upgrading the tube, or just going to a new monocular?  I have to say that I am sorry that I did not buy one of the filmless WP PVS-7 tubes when they were available.  Using Peter's was quite enjoyable.  I have a full binocular, but that only works hand held.  I enjoyed the ability to use both eyes in the telescope, but in the end, I got rid of the PVS-7s simply because the tube performance was inferior to the monoculars I have.  

 

If you could not find one of these filmless PVS-7 tubes, then I would say it is better to move to a monocular because finding better tubes than what you have will be trivially easy.   If you could get hold of one of these filmless tubes with good specs for your PVS-7 though, that is a different story.  I was quite taken with Peter's PVS-7. I would say on par or better with my F9800VG spec tube, but with what looked like better EBI. 

Edited by Eddgie, 11 October 2019 - 07:32 AM.

[Eddgie]

And one other thing.  The PVS-7 optics are far more complex than the monoculars.  For the amount of plastic and glass they have in the optics, it is amazing that they can deliver the sharpness that they do, but they are not as sharp as the monoculars.  The difference is not at all huge but I have not achieved a PVS-7 view that was as crisp and clear as the monoculars with their simple all glass eyepiece. Now I had always wondered how much of that was due to the tube performance and how much was due to the complex optics, and it was not until I had the chance to view with Peter's filmless PVS-7 that I had an answer.  The answer was that most of the difference was in the tube performance and not the optics.  The PVS-7 does not render stars quite as sharp as the monoculars, but the tube appears to be a far bigger performance limit than the complex optics.  I could be quite happy using a PVS-7 with filmless tube as my only device.  The tube made a world of difference in the PVS-7, elevating the performance to more or less monocular levels . Again, not exactly as sharp but pretty darn close. 

 

The only way I would own another PVS-7 would be if I could get one with one of these high performance tubes.  I simply gave up on the 10130 D/UV tubes.  After four Omni VII tubes, I concluded that they just don't come close to the top tier monoculars. 

Edited by Eddgie, 11 October 2019 - 07:42 AM.

[Gavster]

Great detailed response Eddgie.

I would add that in my experience top quality narrowband ha filters really can make a difference to the nebulae that is visible (and better quality tubes can exploit the narrow bandwidth better.

[Eddgie]

Great detailed response Eddgie.

I would add that in my experience top quality narrowband ha filters really can make a difference to the nebulae that is visible (and better quality tubes can exploit the narrow bandwidth better.

I do agree that the filter is important but SiriusLooker is using the same bandwidth filters I have used many times to do side by side comparisons with the PVS-7s and thin film and filmless monoculars.  Same filters, same targets, side by side, and the PVS-7s always have much more grain and noise than even my F9800VG spec tube (which would be the same specs as Omni VII 10130 D/UV, which I do not think have SN of 28.  I have never owned an Omni VII tube that came close to the F9800VG spec tubes I have owned). 

 

Peter's filmless WP PVS-7 though?  I would trade my thin film monocular for it.  It is that good. 

[Gavster]

I do agree that the filter is important but SiriusLooker is using the same bandwidth filters I have used many times to do side by side comparisons with the PVS-7s and thin film and filmless monoculars.  Same filters, same targets, side by side, and the PVS-7s always have much more grain and noise than even my F9800VG spec tube (which would be the same specs as Omni VII 10130 D/UV, which I do not think have SN of 28.  I have never owned an Omni VII tube that came close to the F9800VG spec tubes I have owned). 

 

Peter's filmless WP PVS-7 though?  I would trade my thin film monocular for it.  It is that good. 

Having tried half a dozen different ha filters of varying cost and bandwidth, it has surprised me how much improvement a quality narrowband ha filter can make. Clearly the quality of the nv tube is important but the filter spec used also has an incremental material impact based on my actual practical experience. My suggestion to Siriuslooker is to aim to optimise each element of the system to achieve a final satisfactory viewing experience.

[jdbastro]

And one other thing.  The PVS-7 optics are far more complex than the monoculars.  For the amount of plastic and glass they have in the optics, it is amazing that they can deliver the sharpness that they do, but they are not as sharp as the monoculars.  The difference is not at all huge but I have not achieved a PVS-7 view that was as crisp and clear as the monoculars with their simple all glass eyepiece. Now I had always wondered how much of that was due to the tube performance and how much was due to the complex optics, and it was not until I had the chance to view with Peter's filmless PVS-7 that I had an answer.  The answer was that most of the difference was in the tube performance and not the optics.  The PVS-7 does not render stars quite as sharp as the monoculars, but the tube appears to be a far bigger performance limit than the complex optics.  I could be quite happy using a PVS-7 with filmless tube as my only device.  The tube made a world of difference in the PVS-7, elevating the performance to more or less monocular levels . Again, not exactly as sharp but pretty darn close. 

 

The only way I would own another PVS-7 would be if I could get one with one of these high performance tubes.  I simply gave up on the 10130 D/UV tubes.  After four Omni VII tubes, I concluded that they just don't come close to the top tier monoculars. 

I own SIX PVS-7s and generally I enjoy all of them.  Only one unit has an unfilmed WP tube and indeed that one provides the best, cleanest, sharpest views.

 

I think a big reason why monoculars 'appear' less grainy than a PVS-7 is because on a monocular only ONE eye is looking at the tube in a monocular vs TWO eyes looking at the tube in a PVS-7.  On many occasions, with one of my PVS-7s, I have closed one eye to see the effect on the view and with one eye, the artifacts produced by the tube are less noticeable than when both eyes are open.

 

So one really needs a tube that is 'cleaner' for a PVS-7 than for a monocular since TWO eyes observe the tube in a bi-ocular PVS-7 config.