Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Night Vision Astronomy 2015: Three Perspectives

EAA
  • Please log in to reply
47 replies to this topic

#26 Eddgie

Eddgie

    ISS

  • *****
  • Posts: 25,606
  • Joined: 01 Feb 2006

Posted 05 August 2016 - 09:53 AM

Remember that the full extent of the comatic fan is quite a bit larger than the human eye can perceive because the intensity drops rapidly as you move away from a couple of Airy Disk diameters.

The Image Intensifier though has no trouble seeing the extension going much further out than the eye will show, so bad coma will indeed intrude into the 18mm field of the intensifier.

 

Because the magnification is quite low though,  the effects of the fan are abated to near the edge of the field.

 

As mentioned by others, it is not objectionable at f/5 but coma is coma, and a coma corrector can indeed help subdue it and present a more pinpoint field. 

 

I generally dispense with coma correction because I am so preoccupied with the enormous amount of detail I can see that I simply don't notice it.

 

At f/4 I might feel different though.


  • dfastronavigator and Rich_B like this

#27 jrbarnett

jrbarnett

    Eyepiece Hooligan

  • *****
  • Posts: 30,162
  • Joined: 28 Feb 2006
  • Loc: Petaluma, CA

Posted 05 August 2016 - 01:58 PM

Check this YouTube video out.  Very nice examples

 

https://www.youtube....h?v=SBFEjSl5nI8

Hmm...what I see in the video is a greenish cast version of what I see under moderately darks skies through a 4" telescope, but without the twinkling and greenish cast.  Under very dark skies, the 4" shows more than is being shown in the video on the same targets; a lot more.  

 

The video maker says they used a 10" SCT (!).  Unless it was from an exceedingly light polluted site (full moon in the city center of a mid-sized city, for example), I'm not getting too excited about NV for astronomy at this stage.  It would be nice to see shots of the same target without NV through the same scope under those conditions but those would be tough to set up so they're apples and apples.   :shrug:

 

- Jim


Edited by jrbarnett, 05 August 2016 - 01:58 PM.


#28 TOMDEY

TOMDEY

    Fly Me to the Moon

  • *****
  • Posts: 5,715
  • Joined: 10 Feb 2014
  • Loc: Springwater, NY

Posted 05 August 2016 - 02:18 PM

Thanx for the reply. Great article! I've been doing a LOT of observing with the I3s since my Mar 14th post. Have built custom 1.1x barlows for the JMI RB-16 binoculars. They slip Into the telescopes from the inside at the bottom of the focusers.That gets the I3s to focus parfocal with the 19mm Panoptics.  The coma stuff I understand and have used correctors on and off ever since Lumicon came out with the early ones several decades ago. I literally try with and without and then observe accordingly. The TV Paracorr improves large field edge immensely. I have noticed that the Lumicon introduces just a touch of spherical (which is of course all over the field, including the Center!) So for high-res center field I pull the CC out. The Tunable Paracorrs adjust to minimize spherical. I also measured the throughput hit of the Paracorr: % Lost = R 3.6, G 5.3, B 7.5 not bad.  CC on my RB-16s is sorta moot because the commercial ones just don't fit the hardware. All I can say is the NV views in use are extraordinary. e.g. M57 with dueling I3s 16-inch binos and 12nm Ha is astounding. The ring is UHC crisp and shows that voluted Mobius structure like a twisted wreath. The central star pops with said filter off. Having instant swap twixt NV and "regular" is wonderful. Tom



#29 Jeff Morgan

Jeff Morgan

    Voyager 1

  • *****
  • Posts: 11,538
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 07 August 2016 - 10:51 AM

It would be nice to see shots of the same target without NV through the same scope under those conditions but those would be tough to set up so they're apples and apples.   :shrug:

 

- Jim

 

 

Getting any imaging technology (film, CCD, CMOS, NV video) to capture a display like the eye sees it is extremely difficult. Kind of pointless IMHO. The detectors all work differently than the eye.

 

I thought the videos were interesting, but not enough by themselves to push me over the edge. Although it is impressive there was that much captured given the "integration" time of a video camera is the frame rate - 1/30th second. But it still didn't give me much guidance.

 

Rather, I looked at the science - the spectral response and sensitivity of the GaAs technology. Based on that, the only place I would expect a conventional eyepiece to be remotely competitive would be on an extremely "blue" target. Not many of those come to mind. Portions of the Trifid. The Witchhead. The Pleiades. Perhaps some face-on spirals with lots of O-B associations in the arms.

 

Most everything else in sky puts out lots of longer wavelengths were the eye sensitivity is dropping fast. Effectively, NV extends the view of the universe by about 300nm. Kind of silly to believe a conventional eyepiece can show as much.

 

And of course I have been reading the reports of the early adopters. One expects such people to be excited and enthusiastic fan boys. What I was really looking for were failures and disappointments. Given the high buy-in I would have expected to hear at least a few Buyers Remorse comments. But I haven't seen them yet.

 

The technology seems to good to be true - just like the original "Dobsonian Revolution" did 40 years ago. That took some time to catch too.

 

So, I took the leap of faith. I wasn't sure Green would be my thing, so I went white phosphor. Results pending.

 

If it doesn't work out? Well, I'll have an awesome rifle accessory - very handy since I observe in bear and mountain lion country. And the local coyotes and javelina will be in for a very nasty surprise.



#30 TOMDEY

TOMDEY

    Fly Me to the Moon

  • *****
  • Posts: 5,715
  • Joined: 10 Feb 2014
  • Loc: Springwater, NY

Posted 07 August 2016 - 11:28 AM

I've been using the NV a LOT now so have opinion based on some experience vs just theory. Bottom line for me it is like another eyepiece but WHAT an eyepiece! Can finally SEE the NIR and that is awesome. And indeed typical stars pick up about one full magnitude. If you can config your scope so the NV and regular eyeps are near parfocal (I did that) then it is very convenient to sample targets with both. Biggest pleasant surprises: Most galaxies look really good with the NV, even face-on spirals. This had Not been true with my older Collins. The new I3 is small and light, about the same as a TV Delos. Screw-on 12nm Ha awesome on nebulae. Many more closeish double stars are popping with NV but invisible with plain eyep (perplexing and nice). I would say if you already have a stable of favorite eyepieces, the NV should certainly be added.



#31 Vondragonnoggin

Vondragonnoggin

    Cosmos

  • *****
  • Posts: 8,619
  • Joined: 21 Feb 2010
  • Loc: Southern CA, USA

Posted 11 August 2016 - 10:32 AM

When talking about expense, it seems to be the biggest hurdle to moving to an NV setup. GaAs tubes are expensive and gain expense the higher the specs which of course is desirable for lower noise floor through higher signal to noise ratios, lower halo values, etc.

 

Hammamatsu is just one company that offers tubes with different spectral responses so it is possible to get a tube that has a peak of say 400nm vs a peak of 600nm as in GaAs tubes. Very expensive, but filter use would be similar to visual use and blue would be available for objects like Merope nebula or Witchhead, etc.

 

As far as I know, no one has found it detrimental to use the standard and more readily available GaAs tubes in observations as the Ha content in an enormously abundant amount of objects seems to be enough to satisfy.

 

There have been a number of new adopters as well as a few older adopters moving to white phosphor tubes vs green, but I think that rather than upgrade my devices to all white phosphor tube devices, I would rather find out exactly how much to get just one tube with a spectral response more inline with visual in a high spec version and try out some UHC and Hb filters for variety. 

 

May need some researching. No hurry for anythng else but current devices right now, but in the future, the prices may drop or availability increase. The demand is driven by military so its hard to predict where the concentration on the technology or the money for it will go.



#32 cnoct

cnoct

    Viking 1

  • *****
  • Posts: 758
  • Joined: 02 Sep 2010
  • Loc: Hawai'i

Posted 11 August 2016 - 10:49 AM

I have yet to see the astronomical benefits of blue response, so far I've been underwhelmed by tubes with high blue response. This includes the Photonis INTENS with it's super blue and extended IR response. Though the blue response must contribute something I've yet to see it do so. 



#33 TOMDEY

TOMDEY

    Fly Me to the Moon

  • *****
  • Posts: 5,715
  • Joined: 10 Feb 2014
  • Loc: Springwater, NY

Posted 12 August 2016 - 04:12 PM

Only small improvements can be achieved without changing the material receiving the incoming photons. Spectral ranges for native quantum efficiency of 50% or higher is approx: GaInP 370-670nm , GaAs 670-900nm and Ge 900-1600nm. The nice thing is that in combination, these three would cover a tremendous range! And that's where cost enters into it. The GaAs, although expensive in our amateur astronomy world, is still a bargain for what we get - performance boot-strapped from research and production developed for defense needs. GaAs just ain't going to get you blue performance. But your eye will (if you are VERY young or have had your cataracts removed). Your eye will not get you NIR, but NV Will ! I had my cataracts removed and replaced with plastic implants a few years ago. Blue is now sharp and Electric Bright! Spiral galaxies Pop. And no more astig or myopia or eyeglasses. The surgeries cost little more than a good NV eyepiece! That took care of the blue deficiency (that we All start to suffer in our 30s). And the Gen3 GaAs NV now gets me amplified Ha plus (bonus) NIR. Pretty cool, really! Another bonus of NV, not often mentioned: You can of course look straight at the target with no need for dark adaptation or even large pupil (NV has no exit pupil because the "eyepiece" is a glorified magnifying glass, not an eyep in the traditional sense). My conclusion/point/opinion is this: NV extends your spectral range. Whether that is worth it is personal to your pocketbook and priorities. It's kinda like, is a Ha solar telescope worth it ($$$) to you? For amateur astronomers very interested in the sun and with a few thou play money the answer is YES! For the rest of us, the answer may well be no.  Tom


  • audioaficionado likes this

#34 TOMDEY

TOMDEY

    Fly Me to the Moon

  • *****
  • Posts: 5,715
  • Joined: 10 Feb 2014
  • Loc: Springwater, NY

Posted 16 August 2016 - 06:07 PM

Nother observation: NV really Needs fast feed to satisfy on most objects, f/4.5 being good. F/10 is likely to disappoint. Below that, inescapable shot noise (scant photons) result in the view being dominated by scint noise characteristic of the device itself. A running boxcar averager (see Collins site) substantially mitigates this, but requires that you view the image with a camera and display to e.g. B&W monitor the get "real time" observing. And at that point it starts behaving more like a Malincam than the presence of real-time. So there is a continuum from direct visual (low QE, best presence) to NV (high QE, decent presence) to running integrated video (high QE sort of presence) to long exposure dedicated astro cam (high QE seen after the fact). With every approach, what you want is max info = good S/N and high QE consistent with how long you are willing to wait for gratification. Conclusion is that there is no "right" approach and also no free lunch.  Note that the NV development for the military is because the "instant gratification" is essentially a life and death need!  Tom



#35 chrisskor

chrisskor

    Lift Off

  • -----
  • Posts: 3
  • Joined: 27 Jan 2017

Posted 07 February 2017 - 09:38 AM

I had opportunity to look through Gen 3 NV goggles on a 18" dob and was blown away by details in planetary nebula.  I believe the NV technology would be a great way to enhance our club's public outreach. 

 

At our observatory in Charlotte, NC we have a 16" F10 classic cassegrain and 24" F5 Newtonian, in addition to collection of 12" and 8" Celestron  telescopes.  Scopes all support 2" eye pieces.

 

I found "Binocular Photon Machine" mentioned, found their web site, however, unable to reach manufacture after repeated calls. All material looks to be a few years old, I don't see anything recent on the web.  I'm not sure if they're even in business anymore.  Is anyone using their product?

 

I also called left messages for Wilcox Engineer as their web site shows what looks like an Orion eyepiece enhanced with image intensifier into a monocular.  Now sure if they still selling finished product or just intensifiers, so far no call back.

 

For a do-it-yourself project, looks like we'll need to purchase on Amazon\Web GEN 3 PVS-7 goggle take them apart and mate then with 2" adapter that allows filters.  Sounds simple, but I'm sure more too it.  What else would we need?

 

Does anyone offer a complete plug-n-play kit?

 

How do you achieve magnification for smaller objects like planetary nebula or galaxies when viewing through GEN 3 NV goggles?

 

Thanks, Chris



#36 TOMDEY

TOMDEY

    Fly Me to the Moon

  • *****
  • Posts: 5,715
  • Joined: 10 Feb 2014
  • Loc: Springwater, NY

Posted 07 February 2017 - 11:51 AM

Hi, Chris. I researched what you mention there. That Binocular Photon Machine looks cool, but all indications are that they couldn't make a go of it as a business. It turns out that the "regular" Gen3 NV monocular(s) are IDEAL. Even better than the Collins (which business also seems defunct). The entire Mono, as sold for mil or hunting use, turns out to be PERFECT for astronomy. All you need is the 1.25 and/or 2-inch adapter. The monocular 1x lens screws off and the adapter screws in and you are ready to go! I found those parts and others. The configured monocular requires more in-travel than regular eyeps to reach focus. The resulting magnification acts about like a narrow-field 25mm eyepiece. To get more mag, you would need a Custom Barlow (which I have also done). I have a few of those with all the adapters, as well as 1x and 3x "true NV binos" ,16-inch True NV Binos and narrow band H-alpha, IR etc. PS the eye comfort is amazing. Even people with glasses can keep them on, if they like. Purists consider use of NV to be, somehow... Cheating!  PS Barlow will only work on otherwise bright objects; NV generally Wants f/4 feed or faster. F/1.5 is ideal. Yep... F/1.5!  Tom Dey



#37 outofsight

outofsight

    Surveyor 1

  • *****
  • Posts: 1,589
  • Joined: 31 May 2015

Posted 07 February 2017 - 03:11 PM

You might want to look at this site.         http://pwang.io/hobb...ro/nightvision/

 

The EAA forum has ample information on night vision devices for astronomy. I'd use the referenced site, and then the Search box in the upper right corner and google. There's plenty of info available and it will be easier to do than is imagined in post 35. You can use 1.25" connections, no need for 2". I'll leave you to your research.



#38 Jeff Morgan

Jeff Morgan

    Voyager 1

  • *****
  • Posts: 11,538
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 08 February 2017 - 02:26 PM

You can data-mine the EAA forum for all kinds of PVS-7 options and strategies. Prices are generally "lower" as the primary markets of military and law enforcement don't like the biocular approach due to lack of depth perception. The secondary market is hunters and firearm owners, and they also are moving away from biocular NV for the same reasons. Fortunately, not really an issue for astronomy, and don't let the "unpopularity" deter you.

 

While these devices are clearly eyepieces, you will not find much under the eyepieces forum. NV has been lumped in with imaging technologies and recently hidden moved under the Observing -> Electronic Assisted Observing forum.

 

It is very true that all electronic devices (imaging and NV) work best with fast optics, but don't let that deter you either. They are useful in slower scopes compared to conventional eyepieces. If you like the NV concept, you can always acquire faster optics (or focal reducers) down the road.



#39 Jeff Morgan

Jeff Morgan

    Voyager 1

  • *****
  • Posts: 11,538
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 08 February 2017 - 02:29 PM

BTW, if you are interested in monoculars, a fairly high-end model hit the other website for classified ads this morning.

 

I mention it only for awareness, I have no acquaintance or financial interest with the seller.



#40 Eddgie

Eddgie

    ISS

  • *****
  • Posts: 25,606
  • Joined: 01 Feb 2006

Posted 10 February 2017 - 10:27 PM

 

For a do-it-yourself project, looks like we'll need to purchase on Amazon\Web GEN 3 PVS-7 goggle take them apart and mate then with 2" adapter that allows filters.  Sounds simple, but I'm sure more too it.  What else would we need?

 

 

Chris, 

Others have pointed you to some useful web sites but i would recommend purchasing form a dealer specializing in night vision.  This way you can get a very clear idea of the performance level of the tube in the device.  You really don't know what kind of tube performance you will get in a device sold on Amazon.

 

As for taking the PVS-7 apart, that is not necessary.  The objective housing unscrews and is replaced by a C mount adapter (NAIT makes I think the best C mount for PVS-7).  It is easy to remove and replace the objective lens.  Takes moments and does not even require a screwdriver.

 

Once the C mount is in place, you can use a 1.25" nose that has C mount male threads screwed into the front of the PVS-7 and it inserts directly into the telescope focuser.  You can also get  a 2" nose, but it may make more sense financially to buy a 1.25" nose because 1.25" H-a filters are far less expensive than 2" H-a filters.  You may want other filters as well, and again, 1.25" filters tend to cost much less than the 2" counterparts.   The C mount also allows you to use low power lenses. 

 

The real question is whether you should use a goggle, or instead go to a monocular.  The big difference is that it is hard to find high performance PVS-7 tubes these days and the tube technology avialable for monoculars can offer far higher performance than is possible to get with a PVS-7.

I have both but I admit to enjoying using two eyes so I use the PVS-7 a lot in the telescope and a night vision binocular for low power work.



#41 Tyson M

Tyson M

    Skylab

  • *****
  • Posts: 4,157
  • Joined: 22 Jan 2015
  • Loc: Alberta, Canada

Posted 12 February 2017 - 02:10 AM

Thanks for taking the time to post this.

I plan to join the NV world in the near future because of the youtube videos made and the post like these by the NV community here.

Thank you all!



#42 Tyson M

Tyson M

    Skylab

  • *****
  • Posts: 4,157
  • Joined: 22 Jan 2015
  • Loc: Alberta, Canada

Posted 12 February 2017 - 02:29 AM

I really like the NV idea with my Vixen Porta II on 2" EQ6 legs and small fast refractor (which I do not own yet).

 

Also I am from Canada and only know of one NV retailer I know of is http://www.brandonop...a-Night-VisionĀ 

 

I may reach out to one of you in the future for optimal set up recommendations for my grab and go :)



#43 Eddgie

Eddgie

    ISS

  • *****
  • Posts: 25,606
  • Joined: 01 Feb 2006

Posted 15 February 2017 - 02:00 PM

I really like the NV idea with my Vixen Porta II on 2" EQ6 legs and small fast refractor (which I do not own yet).

 

Also I am from Canada and only know of one NV retailer I know of is http://www.brandonop...a-Night-VisionĀ 

 

I may reach out to one of you in the future for optimal set up recommendations for my grab and go :)

Small fast refractor is nice if you like small fast refractors, but a better choice for nebula would (in my own opinion) be a slightly larger and much faster reflector.

 

Something like a 6" imaging Newtonian used with a Baader MPCC would be better for Nebula.   A Comet Catcher (f/3.6) would be good to, but you can't use filter wheels with it.  Very fast and low coma though.

 

A 6" f/5 would not need a coma corrector and once again, it is faster, but also much more aperture.

 

For NV (and for imaging with the new video chip based Imagers like the Revolution R2, (which is so darned inexpensive that I my get one myself!!!!) reflectors simply offer the ability to greatly improve nebular views due to the very fast focal ratios they allow. 

 

I bought an 80mm f/6 Apo for use with image intensifier, while it works fairly well, every time I use it  I find myself wishing that it was faster than it is. 

 

I was out in near dark skies in south Texas a couple of weeks ago viewing the Heart Nebula (Wow!  What a glorious sight this nebula is.. One of the best in the sky! ) The Nebula nearly filled the field of view in the PVS-7 on the 80mm f/6 Apo, and while the heart shape was quite clear and there was a lot of structure, I know from using faster telescopes that I was leaving an incredible amount  of faint, fine detail unresolved.

 

I could see this!  Not with the fine detail as shown in the picture, but all of the major structural elements were easy to see.

 

http://3.bp.blogspot...eart+Nebula.jpg

 

I just found myself wishing I was using something like f/4 or f/3.6.

 

That was the first time I had used the small Apo under really good conditions and again, while it worked quite well, I knew that I was being held back by the tight bit and slack reins of the little scope.  I need loose and fast, and the faster the better.

 

This is where it led:

 

http://teleskop-expr...Brennweite.html

 

Here is a 6" f/4 imaging Newtonian that sells for $$300.  This is less than I see some 80mm achromats sell for more on the used market!

 

https://www.astronom...ube_p18868.aspx

 

Since the power is low with something like this, and since the view is real time, it does not matter if the mount is not super stiff.  The short tube also makes less demands on a mount than a refractor with everything hanging out on one end. 

 

Throw in a Baader MPCC, and now you are rompin in the big nebula rodeo in the sky!


Edited by Eddgie, 15 February 2017 - 02:02 PM.


#44 highfnum

highfnum

    Aurora

  • *****
  • Posts: 4,782
  • Joined: 06 Sep 2006
  • Loc: NE USA

Posted 02 August 2017 - 04:47 AM

I've used night vision stuff 

for years 

although I have not posted in this 

forum for a while 

 

Yes it does bring something to the table 



#45 ManuelJ

ManuelJ

    Apollo

  • -----
  • Posts: 1,472
  • Joined: 19 Dec 2005
  • Loc: Madrid, Spain

Posted 21 March 2018 - 07:12 AM

Hopefully this technology will arrive some day to Europe.



#46 Jeff Morgan

Jeff Morgan

    Voyager 1

  • *****
  • Posts: 11,538
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 21 March 2018 - 07:55 PM

Hopefully this technology will arrive some day to Europe.

 

Photonis tubes are not made in the US, and available in the UK:

 

https://www.cloudyni...xies/?p=8457012



#47 ManuelJ

ManuelJ

    Apollo

  • -----
  • Posts: 1,472
  • Joined: 19 Dec 2005
  • Loc: Madrid, Spain

Posted 23 March 2018 - 12:51 PM

Photonis tubes are not made in the US, and available in the UK:

 

https://www.cloudyni...xies/?p=8457012

It is illegal to have one outside US and UK, no?



#48 Jeff Morgan

Jeff Morgan

    Voyager 1

  • *****
  • Posts: 11,538
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 24 March 2018 - 01:49 PM

It is illegal to have one outside US and UK, no?

 

I don't know the laws in your location.

 

Photonis is based in France. Perhaps an email to them would clarify it?

 

https://www.photonis.com


  • The Ardent likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics







Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics