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Night Vision Astronomy 2015: Three Perspectives

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Night Vision Astronomy 2015: Three perspectives.
By:

Eddgie
Night Vision at Unity

Vondragonnoggin

I2 (Image Intensified) Astronomy in Heavy Light Pollution and the Smaller Scope
The Ardent
Night Vision with Large Aperture

Summary

Night Vision technology is a powerful tool to enhance observing. Like any observing method, it had its advantages and drawbacks. Three Cloudy Nights members offer their experience.

Night Vision at Unity

By Eddgie


The Oxford Dictionaries defines Unity as, 1: the state of being united or joined as a whole and, 2: the number one.

One of the most common concerns about using telescopes is the limit of the telescope to show a wide field. We buy ever wider field eyepieces or very small telescopes in an effort to be able to see larger and larger areas of the sky. Along the way to ever wider fields, what we encounter is larger and larger objects and no matter how big the field of our telescope is, we quickly realize that there is always something that our telescope is not quite large enough to frame. My chapter of the article on night vision is focused on using night vision for very low power (1x, which we refer to as "Unity" and fields generally larger than possible even with binoculars.

I live 3.5 miles from the center of Austin Texas, which is now the 11th largest city in the US. My observing conditions are far from great, and often during the summer, a thin haze makes even 3rd magnitude stars difficult to the unaided eye.

For extremely low power viewing, I use two different devices, a Night Vision Depot Micro monocular, and a PVS-7 "Goggle". The goggle is something like a binoviewer. It has one lens and one tube, and the light is split by an internal optical device called a collimator, which brings the image to the rear and splits the light path to two eyepeices. The monocular is as the name suggests, a device that uses one objective and one eyepiece.


The lens and eyepiece focal lengths are about the same, so the result is that when viewing, you are viewing at Unity (1x). I also use clip-on afocal telescopes in 3x and 5x. These are called "Magnifiers" and simply clip over the front of the lens on the night vision device so it makes it very easy to change power. Other chapters will cover the different uses of these extremely versatile and powerful devices, and this chapter focuses on the very low power end of the night vision for astronomy spectrum.

One of the most compelling benefits of unity or low power viewing is the utter simplicity. You can walk out of your front door, with a device, a clip on lens, and a couple of filters, turn on my device, and be observing in a few seconds. There is no tripod, no setup, no need to dark adapt, and no need to stay in one spot. This last point is important because from my back yard, my sky is obstructed by trees in all directions except the south, so with a traditional telescope I have a very narrow strip of sky in which I can observe targets. The night vision devices make it possible to move up and down the street in front of my house and this allows me to clear almost any obstruction in any direction so that I get views around much of the sky. If I want to peer deep into the heart of Sagittarius, or catch M45 when it just gets about the rooftops, I can simply reposition myself by walking a few houses over.

The next great advantage of night vision is that with a simple 610nm pass filter (passes 610nm and near infra-red but blocks medium red and the rest of the visible spectrum) light pollution can be greatly attenuated. Generation 3 night-vision tubes were designed to show near infra-red so that IR illuminators could be used in very low or no light environments to provide sufficient light to view the environment, but not give a position away. This same characteristic makes it possible to use H-alpha filters to observe emission nebula in a way that would be difficult with the unaided eye unless you were in very black and transparent skies. With night vision and an H-alpha filter, very large nebula are available for viewing even from locations with light polluted skies.

Finally there is the low power itself. These devices have a true field of about 40 degrees and an apparent field of 40 degrees, so this means that when you use the standard lens, you are viewing at unity, or one power. With the light intensification, this 40-degree field becomes an almost magical view of a sky so filled with large scale structure that it almost defies description. On nights with good transparency, the southern Milky Way resolves into a fantastic complex of dense star fields, dark nebula, and a stunning array of deep sky objects. While the power I use for this is very low, many of these targets are quite large, and the entire Sagittarius region becomes a glittering showcase of small, bright DSOs. With a 12nm H-alpha filter, the Milky Way comes alive with nebula. Even at 1x, the Lagoon nebula is quite large and striking, but at 1x what is more remarkable is that it can be viewed in the same true field as the Trifid, the Swan, and Eagle nebulas, along with the great Sagittarius star cloud, M7, M22, M11, and many more! And this is all in a single low power field of view! Nebula like the North American are amazingly detailed, and when viewed with the very delicate and complex of the Gamma Cygni, and once again, these two big, beautiful nebula are captured in the same true field. The 5x magnifier provides enough magnification to make these targets quite detailed and interesting.

Off the Milky Way, the 40-degree true field reveals many very large aggregates of stars that can't really be viewed in a standard telescope. The wider the field, the more these very large aggregates seem to spring forward. Traditional large clusters like the Hyades and M45 can be seen in the same low power field, and the context of the sky really changes when you see how magnificent and rich these very large scale objects are. In a traditional telescope, you often trade off light gathering for true field. You can see fainter stars in a target at the cost of losing the framing of the target, or you can frame a target using smaller scope, but this comes at the expense of losing the fainter stars. With night vision, you can frame entire constellations and the reach is quite amazing A typical field will be filled with many more stars than can be easily counted. Entire constellations combine together to make fascinating new structures that in the absence of night vision, can only really be seen by the naked eye when skies are very dark.

Evan at very low powers from my light polluted skies, Orion, Horsehead (though not enough power to see the horse itself) and Flame are easy targets, and at 5x with the H-a filter, Orion is fantastic. The extent of the nebula is greater than I have ever seen using traditional scopes even under dark skies. Seeing it at very low power you get the true sense of scale on this fantastic nebula that is hard to appreciate when using traditional scopes that limit your view to a (relatively) small slice of sky.

This brings me back to my opening where I used the definition of unity: the state of being united or joined as a whole. When I use night vision at very low powers, I feel far more connected to the whole of the Milky Way and the night sky than I ever have before. The large scale structure of the great river of stars that connects our horizons becomes something that is almost alive with a population of stellar creatures great and small, and seeing it at 1x using an image intensified eyepieces I now have a sense of Unity that I have never really experienced using traditional equipment. I don't feel like I am looking at the Milky Way anymore. I feel like I am a part of it and I see the fascinating complexity of its structure in a way that I never thought possible.

For observers with easy access to high elevation dark skies, night vision might seem like a toy. For many of us though, the cost, time, and expense associated with getting a big telescope to dark skies, or even using a small good quality telescope under so-so light polluted skies, night vision offers a compelling alternative or compliment to existing equipment. I know that people perceive the cost to be high, but it does not take a lot of money to move into a decent night vision device. In my opinion, it is worth selling off a two or three telescopes that sit unused, along with a half dozen eyepieces that are gathering dust to enter into a world where portability, simplicity, and low powers make night vision observing easier and more fun than most people ever realized.

It is different, and it is not for everyone. I even used to think that. Having entered into it, I now find myself using low power night vision more than any telescope I have ever owned before and that is the biggest compliment I can pay it.


I2 (Image Intensified) Astronomy in Heavy Light Pollution and the Smaller Scope

By Vondragonnoggin

 

I would like to start off with a brief background of my experience in Amateur Astronomy. In November of 2009, my then 8-year old son had been actively watching space programs and drawing pictures of galaxies and star fields. I had an old pair of Vanguard ruby coated 12x50 binoculars with bk7 prisms I had bought a decade earlier for $40. Never got much use until we both started to look up with them in 2009. My son desperately wanted a telescope to see more. I did too. His mother, remarried and living in another house let me know "I bought him a telescope for Christmas so don't buy him one". Being the avid researcher that I am, I looked at alternatives to keep peace and make my son a happy camper. Her pick - an EduScience 100mm reflector from Toys r Us complete with plastic tripod. My choice to not go against wishes of not buying him a telescope - Zhumell Tachyon 25x100mm giant astronomy binoculars on a heavy duty photo tripod.

We tried to get the scope working, but a shaky mess it was. Meanwhile the binoculars were a giant hit. We both wanted more. After joining Cloudy Nights in February of 2010, having been a silent lurker reading as much as I could, I bought an 8" Skywatcher collapsible dob. My son was perfect height standing to see zenith views. I took the scope out frequently with him. So much so, that I knew I was hooked on Astronomy and started an eyepiece collection.

After a year and a half, and many eyepiece purchases later, my son was tired of visual astronomy and I was not. He still is actively into astronomy, but more on the software side and using programs like Sandbox Universe to test gravitational theory and loves realistic space games that use real physics models. He is 14 at the time of this writing. We had taken the dob to dark skies and viewed nebulae, planets, galaxies, but my backyard location was a light polluted mess and galaxies or faint nebulae were not in reach. I also had three previous injuries to my back that were not liking the dob too much. I sold the dob and bought a Twilight II alt-az mount and an Explore Scientific AR127mm achromat. I began studying about filters. Filters for light pollution, filters for nebulae, filters for control of chromatic aberration in achromats. I loved that scope. It was very capable and to me the views were more pleasing than my dob. It had very steady views being absent of tube currents and quick to equalize.

I decided I wanted to see more. I looked into Astrophotography gear. I also read briefly on Astro Video and a brief report on the Collins I3 intensifier eyepiece. Also a report on the Binocular Photon Machine, a Gen 3 device with panoramic binocular eyepiece.

I decided AP was the way to go and promptly bought an EQ5P GEM, Modified Canon T3i, all the adapters, software, a netbook, etc.

I made attempts. I captured some bad moon shots, I tried focus tricks. I had a rough go of it. I missed my simple alt-az setup and silent viewing with no motors, wires, laptop, and polar alignments. I did not like GEM's!

I sold the scope, mount, camera, adapters, and all related gear to a friend who was very interested and needed good working equipment. The equipment was all good. I was the problem. It was too tedious to me just to see more in my light polluted location. I think I am the world's laziest astronomer!

I bought an iOptron 150mm mak-cass next and went back to visual observations.
I still used binoculars a lot and enjoyed two eyed views, having picked up several other pairs and a couple binocular telescopes in 70mm and 100mm sizes. I missed my refractor though. Saw a deal on an AT72ED refractor used and bought it. Great green color too. I bought better photo tripods with geared center columns and better fluid heads.

I began to research image intensifiers. I asked forum members about the BIPH Binocular Photon Machine. I asked a million questions and found the commercial astro offerings in intensified eyepieces were no longer available. I found out they cost quite a bit too, so I began taking advice on what to look for and started searching Ebay. In the meantime, I was pretty sure I was going to purchase a night vision device soon, so ordered a Skywatcher 120ST and a good dual speed focuser to hold heavy loads. Markus at APM of Germany set me up good. Installed my new focuser and shipped me my 120ST. I also ran across an Ebay deal from Ed Wilcox at Wilcox Engineering and Research for a Litton M942 Monocular with a Gen 3 tube in it, plus a whole bunch of extras like relay lenses for attaching to camera, adapters for SLR lenses, a 3x and 6x objective replacement lens and all for much less than a new Collins I3. I bought the package deal and put the c- mount adapter on after taking 1x objective lens off.

I then did as everyone on my forum suggested. Put on a 1.25" nosepiece and put it in my scope. I bought a few filters at recommendation of others. I bought a 7nm H-Alpha narrowband filter and also bought a 610nm longpass after seeing someone else buy a 695nm longpass. I thought the 610nm longpass would still allow me some hydrogen gas views while cutting light pollution to a reasonable level. I was right! It was brilliant to bring out contrast on clusters, edge on galaxies, globs, Milky Way sweeping.

Meanwhile my views of nebulae were nothing short of awe inspiring. With narrowband 7nm Ha filter, chromatic aberration was a non-issue in the achromat, as I suspected. I did not need to buy a color corrected Apochromatic refractor if only a narrow red notch at 656nm was coming through. Both AT72ED and 120ST were showing me views of Orion like I had never seen. I began to experiment with focal reducers too and found the Antares 2" .5x reducer eliminated vignetting in my device. I bought a used PVS-7 binocular, a military device much like a binoviewer. It was an older A/C housing that had a badly blemished tube ($800). I contacted Ed Wilcox again and asked if he had a Gen 3 MX10130/UV tube used he could sell me. He had one. I bought the tube ($1300) and replaced the blemished tube. From advice on my forum, I contacted Nightline Inc about a c-mount adapter for the PVS-7 so I could put a nosepiece on it. They had one left. I bought it and started using my PVS-7 as a binoviewer eyepiece in my scopes. I had been able to see in both devices, the horsehead and flame, but the Horsehead still required averted vision to see more than a dark shadow in my AT72ED. Much better definition in my 120ST, but still wanted more.

I bought a big Astro Telescopes AR152 F/5.9 achromatic refractor. Having the great results from filtering in my 120ST, I knew the big 6" refractor would give me the brighter view to see the Horsehead with some detail and no averted vision. I was right. I was using all three refractors on faint nebulae now.

Bought a Lumicon Night Sky H-Alpha filter also after looking at filter curves and getting the suggestion from another forum member. This one is a longpass 640nm filter and a little darker than the 610nm. I actually prefer it in the two larger scopes and prefer the 610nm in the smaller. More light on smaller scopes giving a smoother appearance in the intensifier. I found a 3nm Ha on Ebay new for $134 from a seller working for Omega filters. Normally they are very expensive at upwards of $900, but this one was worth the gamble. It is a frequently used filter in worst moonlight scenario. Not the toughest coatings like the $900 plus offering, but if careful with it, works great.

By this time, I am beginning to see a long list of faint nebulae having passed into Summer and beginning of Autumn. After reading a lot more and seeing some of the other forum members? devices, I decided to get a Gen 3 25mm device. A PVS-4 starlight scope. I found a T2 adapter on ebay. The objective catadioptric lens was replaced by the T2 adapter. This one gave me the wider views in my scope but was very large and heavy at nearly 3lbs. View was 65° vs 40° of the smaller 18mm devices I had. Variable gain too, but really only useful in biggest two scopes. The mak150 and AR152.

I tried many filters too. All visual filters for standard eyepieces (UHC, OIII, etc.) were disappointing besides the Baader Neodymium Moon and Skyglow filter. That one was decent for cutting light pollution, which gets amplified in the intensifier much like everything else and makes it a brighter green background and less contrast on astronomical objects, but not as effective as 610nm or 640nm longpass filtering.

I bought 35nm Ha and 685nm IR pass filters. Occasionally I use those as the 35nm Ha filter has a broad enough notch to allow more stars seen while cutting CA to pinpoint stars again. The 685nm is good for galaxy hunting but does not allow Ha to get through. Both get used, but infrequently. I bought an Astronomik 12nm Ha filter as well. By far, the most used Ha narrowband is my Baader 7nm filter, followed by 3nm anytime the moon is out. My 640nm and 610nm longpass filters get about equal time.

I later added a 4" wide single lens binocular eyepiece to my PVS-4 for some two-eyed wide views at low power. All scopes but MCT really operating at low power, but see a ton.

Oh yeah, onto what I have seen from heavily light polluted city backyard viewing!

Small list as example:
Lagoon, Triffid, Omega, Eagle, Cat's Paw, Gamma Ori Area Sharpless, summer globulars in stunning detail, too many Open Clusters to count, over 30 different galaxies, Rosette, California, North American, Pelican, Pac Man, Horsehead, Flame, Flaming Star, Lower's, Iris, Heart and Soul, Crescent, Eastern and Western Veil, NGC6974, NGC6979, Ced214, Cocoon, Cone, Elephant Trunk, Gamma Cygni, Butterfly, Dumbbell, Little Dumbbell, NGC7822, Seagull, Thor's Helmet, IC417, IC410, NGC7762, IC353, NGC2024, Barnard's Loop, NGC1975, numerous meteors, satellites frequently, and the list can go on.

I have seen more in the nearly two years of using Image Intensifiers than the previous 4 years without it. All very easy. All on easy to use Alt-Az mounts with no tracking. I continue to refine equipment, viewing techniques, filtering techniques, and keep asking a lot of questions. I am viewing 98% with I2 eyepieces. I have not lost any interest and it instead continues to grow in both seeing more, using better techniques, and learning about the technology.

I have been given immense help by members of the Cloudy Nights EAA forum the entire time. I try to give back what I can in advice and knowledge, as well as experiment and post results.

I usually start off without an observing plan, but have my smartphone running astronomy apps so I can identify what I find. It is such powerful technology even in small scopes, that the "stumble upon an object" way of acquiring targets for observation seems to work fine for me. I can identify on the smartphone and quickly look for other objects in the near vicinity and see if the intensifier picks it up. I continue to study the same objects a lot too, in order to pick up new details and better my observational skills. It does not do all the work for me! Sometimes the objects are still so faint as to need employment of special techniques like averted vision, scope tapping, peripheral movement detection, etc., to pick up the details. Sometimes, of course, they are just in your face like a photo too.

It has been the best decision in equipment to help really see more without needing to have a mess of wires or go-to tracking mount. I am a DSO fanatic and a Nebula nut. My favorite objects to look at. Planets and Lunar still get a chance with my MCT and standard eyepieces, but it is infrequently that I want to view them. So much to see!

My most used scope is the 120ST on photo tripod w/geared center column and a Stellarvue M2 mount. I use an adjustable observing chair with it.

I have found some great vendors in the business also. The following recommended:

Ed Wilcox - Wilcox Engineering and Research (tested tubes with sheeted specs) -

http://www.wilcoxeng-res.com

 Ken at NAIT - PVS-4 best T2 adapter I have tried, PVS-4's, PVS-7's, c-mount for PVS-7 B/D body. -

http://www.nait.com

Mo at AE Optics - PVS-4 parts. -

http://www.aeoptics.com

Night Vision Depot - one of the best companies to deal with for tubes, goggles, and the best monocular I have tried for astronomy - The NVD Micro Monocular which has a built-in c-mount and is adapted easily. -

http://nvdepot.com/

Glynn at OwnNight - devices, tubes, repairs -

http://www.ownnight.com

Bruce at Night Vision Universe - devices, tubes, parts, great pricing.

http://www.nightvisionuniverse.com

Nightline Inc - devices, parts, had my PVS-7 A/C c-mount adapter, great guys.

http://www.nightline-inc.com

RafCamera - ENVIS adapter for 1.25" filters

http://www.rafcamera.com/en/adapters

Agena Astro - adapters, threaded extensions, filters, etc -

http://www.agenaastro.com

Scopestuff - adapters, nosepieces, reducers, threaded extensions, etc -

http://www.scopestuff.com

Many more on ebay and many of these I listed had ebay storefronts.

Image Intensified Astronomy may not be to everyone's taste. There are naysayers apprehensive about green views, there are photon purists, there are those that simply want traditional methods, but it certainly fits for me.

 

Night Vision with Large Aperture

By The Ardent


This year I read some very interesting reports of night vision astronomy on Cloudy Nights. I decided to try it for myself. I?m a longtime visual observer and gear head. My city backyard prevents observation of most galaxies, nebulas, and dim planetaries. I can't see the Milky Way. While I make good use of what I have, it's frustrating to log yet another "not seen" target.

I purchased the PVS-7 night-vision goggle. It features a lightweight, waterproof, shockproof housing. 2 "AA" batteries provide weeks of use. Focuses like an eyepiece, no OCS or Barlow needed to reach focus. Two-eyed viewing with excellent collimation and no merging issues. C-mount adapter accepts numerous lenses and accessories. Works right out the box with supplied lens. Used with a dob, the goggles give a correct view image. This matches the view in my right-angle correct-image finder. It matches my star charts, my binoculars, and my naked eye view.

It does have some drawbacks: cost, green color, scintillation, narrow 40-degree field, 26mm eyepieces provide low magnification, not suitable for every telescope or target. Hexagonal "honeycomb" background pattern visible in bright environments.

The first night I used the PVS-7 with the supplied 1x lens and a Hydrogen-alpha filter. I saw the Gamma Cygni nebulosity, IC 1396, NGC 281, and best of all, the California nebula! I was hooked!

My main telescope is a Teeter 18" f/3.5 dobsonian. I couldn't wait to try the PVS-7 with the large aperture. Some accessories are required. The components of my night vision system:

PVS-7 NV goggle from NAIT with C-mount adapter.
http://nait.com/products-night-vision/night-vision-goggles/night-vision-goggles/

C-mount to 1.25" adapter/ or 2" adapter. The 2" has threads for both 2" and 1.25" filters.
http://www.scopestuff.com/ss_c2b1.htm
http://www.scopestuff.com/ss_c2bf.htm

Or C-mount to 1.25" adapter/ 0.63x focal reducer combo
http://agenaastro.com/agena-c-cs-mount-focal-reducer.html
The focal reducer almost doubles the field of view, but coma becomes noticeable with the focal reducer.

Astronomik 12nm Hydrogen Alpha filter, 1.25 or 2". This is critical for viewing nebulae, but strongly attenuates stars.
http://www.astronomik.com/en/photographic-filters/h-alpha-12nm-ccd-filter.html

Baader 35nm Hydrogen Alpha filter. Weaker nebulae response, but more stars visible. The Lumicon Night Sky h-alpha filter did not provide enhanced nebula viewing.
http://agenaastro.com/baader-h-alpha-35nm-ccd-filter-1-25.html

Baader 610 nm Longpass red filter. For removing sky glow and light pollution for viewing galaxies, clusters, and other non h-alpha targets.
http://agenaastro.com/baader-red-filter-1-25-fcfr-1-2458307.html

Just like in astronomical imaging and solar observing, Hydrogen alpha filters play an integral role with night vision. Normally invisible or impossible targets like Sharpless nebulae and PK planetaries are visible, depending on their H-alpha emission. Oxygen III won't help here, night vision responds poorly at this wavelength.

Viewing nebulae with the 18" scope:

M8, M20, M17, M16. These famous prominent nebulae are just magnificent with night vision. Add an H-alpha filter, and the view is comparable to a long exposure image. "Simply glorious" seems a lacking description.

Gamma Cygni Nebula (IC 1318): With 12nm H-a, extensive detailed nebulosity. Lots of dark lanes and dust blobs strongly silhouetted against the bright nebula. Spans several degrees. Very similar to long exposure images.

Crescent Nebula (NGC 6888) Unfiltered: Only brightest part corresponding to visual observations seen. With 12nm H-a: complete loop seen. Mottling visible, especially on eastern loop, like "leopard spots"

North American Nebula (NGC 7000) Only vague outline faintly visible unfiltered. With 12nm H-a, sharp detail of wisps and concentrations of nebulosity mixed with dark lanes. "Mexico" region like a long exposure image, contrasting with dark "Gulf" Lovely prominent double star Espin 1451 visible along brightest part.

Sharpless 2-88: bright and obvious with 12nm H-a. Separate bright nodule seen.

Sharpless 2-90: like a fat lopsided crescent moon. 12nm H-a

The Elephant Trunk (IC 1396) Large extensive nebulosity with dust lanes. The "trunk" directly visible directly with 12nm H-a

The Pac Man (NGC 281) Only tiny brightest part visible unfiltered. With 12nm H-a, bright with distinct edges and scalloping. An imaging buddy found the live view similar to his H-alpha channel.

The Bubble Nebula (NGC 7635) This was observed from home in the city, full moon, and thin cirrus overcast. Visual versus night vision compared.
13mm eyepiece and Paracorr : no nebulosity, just stars seen
13mm eyepiece, Paracorr, and Oxygen III filter: some nebulosity seen with averted vision, very faint.
PVS-7 unfiltered: small rectangular nebula touching bright star. Honeycomb background of image tube interferes.
PVS-7 with 35nm H-a: nebula clearly seen with structure. Bubble evident. No artificial background.
PVS-7 with 12nm H-a: Bright knots in rectangular nebula. Bubble clearly defined. Dark lane to north, then more nebulosity, a division similar to the Lagoon Nebula

Cone Nebula (NGC 2264) Immediately obvious with 12nm H-a! Last year we observed this under dark skies with a 30" dob. Only visible faintly, with a H-beta filter.

Hubble's Variable Nebula (NGC 2261) Bright and detailed with unfiltered view. Dim and attenuated with 12nm H-a.

Horsehead (Barnard 33 and IC 434) Easy and obvious with 12nm H-a.

Gamma Cassiopieae Nebula (IC 59 and IC 63) Not seen unfiltered. Only IC 63 seen with 12nm H-a. Large with irregular shape.

Planetary nebulae:

NGC 6842: Invisible unfiltered, faint ghostly disk with H-a.

The Ring (M57): Transparent disk unfiltered. Opaque ring structure with 12nm H-a.

Dumbbell (M27) Like the Ring, this bright planetary isn't really a candidate for night vision. It does show interesting structure however. Unfiltered just the dumbbell shape is present. This corresponds to the pink-red "apple-core" area seen in images. Many faint stars seen in the nebulosity, but the blue central star is difficult. With 12nm H-a, the "apple-core" overlays the round body of the opaque nebula. No embedded stars visible.

NGC 7048: Not seen unfiltered. Easily seen round disk with 12nm H-a.

NGC 7027: Bright oval nebula with hint of dark lanes unfiltered. Definite dark lanes separate the nebula into three unequal lobes with 12nm H-a.

NGC 7026: Tiny, two bright flat ovals separated by dark lane unfiltered. Nebula larger with 12nm H-a. Looks like images on Internet.

NGC 7662: Nice detail with spherical outline unfiltered. Bright figure-8 inside elliptical envelope with 12nm H-a.

Sharpless 2-188: invisible unfiltered. With 12nm H-a, obvious, nice fat crescent like a coarse brushstroke. Barely visible under dark skies with a 30" dob and normal eyepiece + OIII filter.

P 84.9+4.4 (Abell 71) Not seen unfiltered. Large ghostly round disk with 12nm H-a.

P 103.2+0.6 (Minkowski 2-51) observed during full moon and cirrus overcast skies, in the city. 13mm eyepiece with OIII filter: not seen (was previously seen, barely, under dark skies) PVS-7 with 35nm H-a: faintly seen with central star.
With 12nm H-a: Disk clearly seen but central star attenuated by filter.

P103.7+0.4 (Minkowski 2-52) observed during full moon and cirrus overcast skies, in the city. Same results as above, but much smaller disk with no central star.

Only about 1 in 5 PNG/PK planetaries observed with night vision were visible.

Galaxies:
Viewing galaxies was an unexpected bonus. Just a red filter in the city, or no filter under dark skies. A 2x Barlow helps with resolution. Like with normal visual observing, galaxies are much improved under dark skies. Surface brightness correlates with visibility.

NGC 7331: looks like a small M31. Four satellite galaxies visible in FOV.

Stephan's Quintet: all five visible from my light polluted backyard!!! I was sooo happy!

NGC 185 and 147: Satellites of M31 located about 5 degrees away in Cassiopeia. Not terribly bright, and 147 is difficult visually. Both are easy with night vision.

NGC 1275 (Perseus A) Easy with night vision, and about 15 other small galaxies seen in FOV, part of galaxy cluster Abell 426)
The fainter galaxies are challenging.

NGC 253 (Sculptor Galaxy) This bright target is stunning visually, even more so with night vision. Tiny, thin dust lanes visible around the core.

Not every galaxy works with night vision. Low surface brightness Barnard's Galaxy in Sagittarius and M33 aren't improved over visual.

In closing, the night vision experiment was far more successful than I expected. The view is upright and correct. No computer or cables required. Otherwise invisible nebulae and galaxies are visible, even from the city.


  • Jeff Morgan, Relativist, GeezerGazer and 17 others like this


43 Comments

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StarMike8SE
Jan 08 2016 09:41 AM

Great review and a lot of great information.  Thanks for posting

    • flygary likes this
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Jeff Morgan
Jan 09 2016 02:44 PM

Ever larger and faster mirrors are a financial, logistical, and thermal dead-end for me, NV sounds very tantalizing.

Jeff

Thursday night I observed, for the first time, four galaxies 1/2 degree south of Castor: IC 2193, 2194, 2196, and 2199. They were all easy with night vision in my 18" dob. Now consider the conditions: in a red zone Bortle 7 per Clear Sky Chart, 90% humidity, and direct glare from 4 streetlights. 

These are targets I would never even consider observing from my backyard with normal eyepieces. 

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Doug Culbertson
Jan 10 2016 05:24 PM

 Good article!

 

A few years ago I had the priviledge of observing through a Collins I3 and was blown away. NV has been on my mind ever since then.

I currently live in what used to be a blue/green zone that has degraded to a yellow zone at best as the city moves closer. As faint fuzzies get fainter and fuzzier here I have been thinking about NV more and more. Thanks in no small part to the EAA forum and the guys who wrote this article, I just bought a used PVS-7 with very good specs. While expensive, it is a whole lot less expensive than buying land in a darker area, as we had been considering.  I am looking forward to more years of observing from home thanks to this technology. 

Great review. I viewed The Ardents night vision set up last fall at the Staunton River star party. I was very impressed. I kept leaving my 30" scope to go over and peek thru his. He brought the setup over to my scope and we tried an experiment. We went to SH2-188 with an eyepiece and we barely noticed a wisp. We put in the Night Vision setup and there it was in full view. Lots of fun. I may have to get one of those :-)

 

Duane

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Jeff Morgan
Jan 11 2016 02:10 PM

A question to the authors, as trailblazers in this application:

 

What is the outlook on using the NV tube afocally? That is, using some type of bracket and mounting it to an existing eyepiece.

 

I recall a thread on this some months ago, with the speculation that a quality zoom eyepiece could be a winner since it would allow an easy and fast method of changing image scale (I do own a Leica ASPH). Any updated news?

 

In addition to be able to vary effective magnification, my thinking is this method may be more favorable to the slower focal ratios of my scopes (f/7, f/8.5, and f/9). At the eyepiece, the device really shouldn't be able to tell if the optics are f/1.2 or f/22 should it?

:shrug: Those answers are way above my pay grade. I've only been at this for a few months.  :scratchhead:

I can't say what works for me will work for you. I'm my case, the device is the eyepiece. I believe my success is due to having a fast large aperture scope. I applied night vision to what I was already doing and familiar with, and it works. 

 

I think night vision now is far more accessible than in the past. I remember 10-15 years ago the ads for the Collins I3 eyepiece (an observing buddy has one ) About 5 years ago there were some articles about the BIPH, but nothing lately. 

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Vondragonnoggin
Jan 11 2016 06:33 PM

A question to the authors, as trailblazers in this application:

 

What is the outlook on using the NV tube afocally? That is, using some type of bracket and mounting it to an existing eyepiece.

 

I recall a thread on this some months ago, with the speculation that a quality zoom eyepiece could be a winner since it would allow an easy and fast method of changing image scale (I do own a Leica ASPH). Any updated news?

 

In addition to be able to vary effective magnification, my thinking is this method may be more favorable to the slower focal ratios of my scopes (f/7, f/8.5, and f/9). At the eyepiece, the device really shouldn't be able to tell if the optics are f/1.2 or f/22 should it?

 

Jeff,

 

  I am using a Baader Zoom for afocal viewing like you mention, but you need to start with relatively fast focal lengths to begin with to keep the image bright with less noise and scintillation. I wouldn't recommend slower than F/7 and preferably faster. I found using the Baader Micro-Stage II click stop digiscoping adapter works very good using a Night vision depot Micro Monocular coupled to the Baader Zoom. There is a thread on it in EAA forum started by me. The Image Intensifier does care about focal ratio still but not to the extent described in afocal imaging with a camera wiki. It sems to work more as you suggested - like a teleside converter, but cannot confirm that is the exact behavior until I make more comparisons. There is some dimming with increased magnification.

 

The NVD Micro has a 28mm ocular (approx). The Baader zoom is 24-8mm, so quite a bit more magnification and attaching the Micro Stage II clamp to rotating part of the zoom allows for a 180 degree twist through the magnifications. This resulted in greatly increased magnification without darkening the image or increasing scintillation as much as using a 2x barlow, but at the expense of eyepiece aberrations also coming through the Micro such as EOFB which was very noticeable after image intensifier amplified the view. Not so bad that I won't use it again though. To increase image scale as much as it did with the zoom in my 120ST would have required a much longer focal length (thereby increasing focal ratio if same size scope objective is used) or larger aperture with focal ratio still fairly fast. Neither of which is desirable to me. I am a small scope enthusiast, so it has to work with the smaller scopes I have. I had good success so far but have only had the setup out three times and some more comparisons to do, but looks to be a promising setup.

 

I don't think it is possible to attach the PVS-7 using one of the handy digiscoping adapters, but maybe some adapter could be made or bought. I use the Micro Monocular for this as it is perfectly suited right away with no extras needed.

 

Here is the thread on it - http://www.cloudynig...ro-afocal-work/

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These are good articles and reflect the excitement possible with gen 3 equipment.  I have used a Collins I3 for over a dozen years from both light-polluted and dark sky sites.  I can not imagine living without one.  My largest scope is 10" but when viewing a favorable target it behaves as if it is 3x that aperture.  The initial price may look high, but when amortized over decades it really is inconsequential.

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Thanks for the great article and now discussions.  I posted "elsewhere" brief comment regarding Night Vision at 1x with very little response.  Anyway, about two months ago I got TWO Gen3 Micros with 12nm pass H-alphas  - turned them ON and just hand-held one to each eye. My life will never be the same!  Totally unexpected was that at matched 1x ... It's like looking thru an enhanced H-alpha Window --- doesn't feel like binoculars or electronic cheating vision at all !  Honest: I am able to SEE the Horsehead (as a very small but distinct "notch").  And the Milky Way is just Loaded with obvious Ha features all over. North American, Pelican, California, Gamma Cyg butterfly-shaped thing, Rosette, Barnard's Loop --- all that stuff and much more just blazing across the sky.  I tried left only, right only and both. With two completely separate but matched I3s one thing is patently obvious:  Two is way better than one, WAY better.  I believe several things contribute to the enhancement (perceived brighter, better contrast, resolution, far less noisy): 1) The usual bino advantage - we have two eyes and the feeling of reality requires both. 2) The scintillation twixt L/R is completely uncorrelated - so brain effectively  filters it out. 3) The brain co-adds the correlated info and completely convincing; it looks twice as bright with both eyes! 4) Restatement of #3 applies also to far better contrast perception. 5) Both sample different atmospheric columns (to each field point) so uncorrelated atmospheric scint is effectively filtered out (ignored) by Visual cortex. 6) Ditto that regarding uncorrelated imperfections in the eyes (floaters, shot noise, neural path noise, blind spots, aberrations, etc.) Bottom line is - astounding views!  I also used (mono) on my 29-inch Dob.  Holy Cow!  The Horsehead looks like the photos (structure, brightness, resolution).  M42 is so bright I sampled it only briefly so as to not damage the tube!  The fluffy tendrils way out show magnificently.  Technical:  One thing that pleased and somewhat surprised me:  Because each side is operating at accurate 1x, it is not at all critical to have the two intimately aligned.  Just hand held one in each to each eye and the images merge just fine!  Honest - It feels just like looking thru a window to the Universe.  So I'm all excited and hooked.  Next:  I have JMI RB16s and just recently amended custom - very weak, 1.1x - Barlows to bring the two I3s parfocal with my Panos and Naglers.  Haven't had a favorable night yet but expecting spectacular views.  My background includes working in Visual Science at the U or Rochester (NY).  Well, I'm going to read the article more slowly now.  Thanks again!  Tom Dey

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Perseus_m45
Jan 19 2016 01:16 PM

Has anyone tried NV on close doubles ?

My experience: Not really the best for close doubles. Good for multiples with faint components, like 14 Aur or 59 Cyg.

With my dob, the night vision device gives 61x and 0.65 deg FOV. Looking at M81, there are two close doubles to the SW. Struve 1387 is easily split at 9", while Struve 1386 is not resolved at 2"

Check this YouTube video out.  Very nice examples

 

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

    • Bob S. likes this

Thanx for the link, Peter. That is well-done and certainly looks a lot like it feels to use visually. I do note that my vis I3 shows notably more "pin-point" star images though. Not sure why. Maybe the foreoptics or cam focus in the video? When I had done video years ago with a Collins - same problem. Video not as good as looking thru.  Tom Dey

It is nice to see that image intensifiers are getting some newly awakened press. Since the early days of Bill Collins putting out the I3 image intensifiers, many of us have been enamored with the views. My first views through one were from a neighboring 12" telescope at a Winter Star Party in about 2003 when the owner of a Collins asked if I wanted to see the Horsehead Nebula. I was shocked with what I saw. Well, about 6 or 7 image intensifiers later, I am still a big fan of the device and have a customized Micro IIE. Bill Collins did not have the mil-spec quite right in using a TeleVue magnifying lens that was only 7x whereas the military has found that magnifying the photocathode tube views x12 is more optimal. I learned this after being in contact with one of the country's leading experts on night vision devices who happens to live in Hawaii and he sent me a Micro IIE to compare to my Collins. The Micro showed me just a bit more contrast and better views and I sold my Collins I3 at the time. He used to actually jog at night with a binocular night vision device. They are a great compliment to both conventional eyepieces and astrovideo cameras and bridge the gap between the two genres very nicely. One night, about 5 years ago, I aksed Al Nagler if he would like to see the Flame Nebula and the Horsehead nebula in one of his TV NP127's. He was delighted with the views since he had never seen those objects through his own 5" refractor.

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Is there a color version?

Hi grao, regarding color: The gallium arsenide photocathode responsivity peaks in the red/NIR spectral range. And the phosphor screen is plain greenish or white. One could theoretically reconstruct (spectrally-shifted) color...but would be complex to say the least. The closest I have seen in a mil-spec device is ITT combined NV + Thermal. The NV is green and the thermal is orange. Those signature Fused colors are vivid because of the color contrast. Mil utility is obvious. The 1x monocular was amazingly compact, rugged and ... $15,000. I fell in love with it and then handed it back. Not really for astronomy, although I expect meteors would look amazing.  Tom Dey

Thanks Tom- I guess a close approximation would be a Mallincam hooked to one of those eyeglass monitors!

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Jeff Morgan
Feb 05 2016 10:31 PM

As I contemplate where NV could fit in, one natural fit comes to mind - the owners of large Dobs. The reasons:

 

1) Already own "fast" optics;

2) Interested in "going deep"; and

3) A demonstrated propensity to spend money.

 

I am getting way ahead of myself, but I think the question is a good one for those NV gurus who have "been there done that".

 

Q: Given the sensitivity of NV to the longer wavelengths, would the user of a truss dob experience artifacts (such as sky brightening) from his own body heat?

I use both my PVS-7 D and my NVDepot Micro in my 12" open truss dob from my back yard with no problems at all.

 

These devices do not really see bad effects at all other than at some angles the glare from the back porch light can get into the secondary box and cause glare.

 

I leave the porch light on though (it is on a dimmer and is a down-light so is somewhat baffled) because one of the great things about using night vision gear is that you don't have to stay dark adapted, though the automatic brightness control on the device will greatly dim the image if you are really out in the dark, so you do get partial dark adaptation, and if you are using a monocular, one eye will get fully dark adapted.  This was supposed to be one reason the military went to monoculars (one eye would always be full dark adatped for better situcuational awareness... At least that is what people say, but I think it was because it is smaller and lighter, sharper, can be mounted on a rifle, cheaper to make, and has a slightly sharper image).

 

Anyway, I use mine on an open truss dob and have absolutely no problem.

Should say this too... In the Comet Cather, it is a bit different story.  This scope does have problems with distant light getting inside the OTA.  I need to make a very short dew shield type baffle for this one.  Mostly it is OK, but I am in the habit of taking it outside and holding cradling it in my arms to wander down the street with it so I can get better vantage points closer to the horizon.

This scope clearly is getting off axis light spilling in.

 

Now maybe if I could walk down the street with my 12" dob in my arms I would have this problem too,  but since I can't do that, I don't have that problem.

 

This means that if there is any light source near the horizon where light can get into the tube, it could be a problem so I can't say an open truss will be completely OK because it could be that some light from somewhere could get in but as a rule, I don't have any problem at all.

 

One last thing.  With the NV in the Comet Catcher, I see stars that I struggle to see in the 12 dob using averted vision.  This means that walking down the street with the comet catcher in my arms is like carrying my 12" dob.

 

It is crazy good stuff.

 

I have sold off pretty much all of my high end scope stuff to go NV and have not regretted it.  I use the NV stuff far more often and see far more with it than ever.

 

I do more and more of my observing at very low power, but when I plug it into the dob, it is a major wow.  Like doubling the aperture.

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Jeff Morgan
Feb 15 2016 02:16 PM

An interesting question comes to mind for the Ardent, as well as other fast scope NV users:

 

1) For Newtonians, Paracorr, or non-Paracorr?

 

Also, I am guessing the integrated eyepieces in NV devices are "simpler" designs, not the "fully corrected" eyepieces the slick glossy advertising tells us we must have for a satisfactory viewing through a fast telescope.

 

2) How do NV eyepieces do at the faster focal ratios? 

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Doug Culbertson
Feb 16 2016 02:30 PM

Jeff,

 

I have only used my PVS-7 once in the 11" f/5, and that was sans Paracorr. Coma was evident in the outer 20% of the fov, maybe a bit more. I was so mesmerized by the view that I didn't really notice the coma at first! Next time out I will try the Paracorr to see how that works out.

 

I think that the eyepieces are most likely a simpler design, given the 40° or so fov. FWIW, that 40° seems really wide when observing at 1x! they do seem to be pretty well corrected though.

 

My fastest scope is f/5, and I loved the views. I may actually end up with a focal reducer to see how that works out, as the Horse Head was pretty much in my face at f/5, and I would like to try out a bit wider fov in the scope.

 

Keep in mind that I am probably the most recent NV astronomy convert around, so take my experience for what it's worth.

Catching up here: Ummm ... regarding coma: the NV field is small - gallium arsenide photocathode is only 18mm, so coma of the feed optics will generally not be problematic at all. But even the good integral "eyepiece" (actually a multi-element magnifying glass) renders the field edges not so good unless your eye is very well centered. Some custom mil applications use bigger photocathodes and/or flaring fiber optic image inverter - but those are very $$$. PS I've now used my Micro IIEs a lot and love them. So much so --- that I stare at my collection of Naglers and Ethos - and wonder why I have so many. BTW - A machinist friend modified a shorty barlow to fit the Micro. That's the only way to get parfocal 2x. That helps on close doubles a LOT! Otherwise, the NV is "stuck on" low mag (approx equiv to mag of a 25mm eyepiece).  Tom Dey

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.

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