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Night Vision Intensifying Eyepieces

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#76 Eddgie

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Posted 21 March 2018 - 09:32 AM

Someone asked why the view dropped off when moving from the center of the field.   There are two possible reasons.

 

The first (and in my opinion, probably the most common) is vignetting when using lots of focal reduction.  Reflectors in particular are generally only designed to fully illuminate maybe a 10mm image circle and this means that if you reduce the field by 50%, the fully illuminated image circle is now only 5mm.   Many refractors running focal reducers will also suffer off axis illumination falloff because of vignetting in the front of the focuser tube, or in the light path.

 

I have a 6" reflector that works at f/2.8. It was designed to fully illuminate an APS-C size sensor when working at f/2.8 so my field is very bright all the way out to the edge with even a 7nm filter (have not tried it with my 5nm yet).

 

The other reason is that when the system gets very fast, the Ha filters can suffer from band shift.  As the light entering from the objective comes in at steeper and steeper angles from the edges of the field, the narrow band pass starts to shift off of the Ha peak.  Now again, I use an f/2.8 scope and even with an 7nm filter, the amount of band sift I see is very mild so this is why I think that many times the falloff people report is likely due to vignetting.

 

At 1x and 3x, though the light cone is usually between f/1 and f/2, and here, the 7nm and 5nm will show significent band shift.   Under dark skies, I use a 12nm and this will show very little illumination falloff.  At 1x  under dark skies I can see the entire Barnard's loop and Angelfish Nebula in the same field.

 

So, falloff is often vignetting from the primary optics and even at f/2.8, a scope designed to fully illuminate APS-C size sensor should show little sign of falloff.   Faster than this and the width of the band pass can start to be an issue.

 

This picture was taken by one of our members.  This Cygnus like you can never see it using conventional eyepieces.   Because it is f/1 and probably using a 5nm filter, you can see how the view looks vignetted, but again, this is actually more a function (in this particular case) of band pass shift as you get further off axis.

 

Someone asked why there are so many reports from 1x views.Look carefully at this picture!  Can you see The North American Nebula? That should easy of course, but this is a 40 degree true field.  The "Butterfly" in the middle is a super bright part of a nebula that most astronomers using standard eyepieces will never be able to see and probably only seen as Gamma Cygni Nebula on charts, but most of the nebula in the center of the field is the part of this complex.

 

Can you see the Pelican?  The Veil?  In the original, I could even pick out the Crescent Nebula (visible at 1x).

 

gallery_139776_8407_153279.jpg

 

 

This is why so many people using NV work at 1x and 3x a lot.  There are views so full of nebula that it simply won't all fit into smaller fields.

 

 


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#77 Eddgie

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Posted 21 March 2018 - 09:38 AM

And again, this is not at time exposure. While it does take dark skies to see the full nebula shown in the above picture, you can easily see all of this in real time.   The amount of nebula visible in the Milky Way under dark skies totally redefined my understanding of the galaxy we live in.

 

Frankly, galaxies are boring to me now.   The most astonishing DSO of all time to me is the Milky Way at 1x.  It is staggringly rich with gas clouds and star concentrations.   

 

(The other appeal of 1x and 3x is that there is no setup or take down time, and no mount required.    I can observe while taking out the trash at night.  I used to tell people not to be surprised if low power observing became their most used method of viewing). 


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#78 Doug Culbertson

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Posted 21 March 2018 - 10:40 AM

 

 

(The other appeal of 1x and 3x is that there is no setup or take down time, and no mount required.    I can observe while taking out the trash at night.  I used to tell people not to be surprised if low power observing became their most used method of viewing). 

 

You told me that back when I first got into NV, and you were right. I observe with my NV at 1x-7x far more often than I bother setting up a telescope. Of course, when you can use a telescope sufficient enough to perfectly frame the Rosette, that's a kick in the as, uh, rear end as well.


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#79 Jeff Morgan

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Posted 21 March 2018 - 10:51 AM

And again, this is not at time exposure. While it does take dark skies to see the full nebula shown in the above picture, you can easily see all of this in real time.   The amount of nebula visible in the Milky Way under dark skies totally redefined my understanding of the galaxy we live in.

 

Frankly, galaxies are boring to me now.   The most astonishing DSO of all time to me is the Milky Way at 1x.  It is staggringly rich with gas clouds and star concentrations.   

 

(The other appeal of 1x and 3x is that there is no setup or take down time, and no mount required.    I can observe while taking out the trash at night.  I used to tell people not to be surprised if low power observing became their most used method of viewing). 

 

What gave me the real impetus to start this journey was the Perspectives article:

 

https://www.cloudyni...spectives-r3028

 

And at the time I read the portion on the 1x and 3x observing and said to myself "Yea, right. Nice, but after a few minutes of that I'll move on to the telescope views." Given my past history of frequently-owned and rarely-used dust collecting binoculars, it made sense.

 

Oh no! Low power NV observing is absolutely captivating. Sure, I mostly use the device as a telescope eyepiece. But perhaps 1/4 of all my viewing now is low power hand-held. Fast, easy, convenient, and rewarding.

 

At the end of a long day when I'm too tired to drag out equipment (or winds/weather are too marginal), it's so easy and relaxing to plop down into the zero gravity recliner with a handheld device.

 

Telescopes, when pointed to certain areas of the sky get you Galaxy Clusters. Low power NV gets you Nebula Clusters, bright and rich in detail, as the photo above hints at. Many of those nebulas were previously the province of astro-imagers. Now, I see them in real-time from a yellow light pollution zone.


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#80 Doug Culbertson

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Posted 21 March 2018 - 11:50 AM

Reading back through this thread and I just had to add; seriously, some of you guys never thought to use a Ha filter on  your NV device for planetary nebulae before? I've been doing that for two years now and I have had my best ever views of M27, M57, NGC 6543 (Cat's Eye), NGC 2392 (Eskimo) and several others. I thought that I had posted that in EAA awhile back.

 

Anyway, I'm glad that some of you are discovering the joy of PNs in Ha. smile.gif



#81 moshen

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Posted 21 March 2018 - 01:08 PM

One of the best things I've found with NV is the 1x and 3x views. It gives me much more context in our place in the galaxy and universe than telescope views. Telescope views can be like going to the Grand Canyon and looking through only the viewfinder of a camera with a large telephoto. The best view is often at 1x or 3x and as Eddgie says I can pull the entire thing out of a jacket pocket. It really redefines Grab 'n Go.

It was one of the reasons that justified the large cost of NV. You're investing in a completely separate instrument, not only just another eyepiece. Many folks have as much invested in much less versatile instruments. Such as expensive small refractors (guilty) or Ha solar setups.



#82 Starman81

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Posted 21 March 2018 - 01:49 PM

Reading back through this thread and I just had to add; seriously, some of you guys never thought to use a Ha filter on  your NV device for planetary nebulae before? I've been doing that for two years now and I have had my best ever views of M27, M57, NGC 6543 (Cat's Eye), NGC 2392 (Eskimo) and several others. I thought that I had posted that in EAA awhile back.

 

Anyway, I'm glad that some of you are discovering the joy of PNs in Ha. smile.gif

Thinking back to last year, I'm sure I've checked out the Dumbbell and was thoroughly impressed but as for any others, I would definitely have to take a look back at my observing reports. 



#83 faackanders2

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Posted 22 March 2018 - 07:02 PM

Thinking back to last year, I'm sure I've checked out the Dumbbell and was thoroughly impressed but as for any others, I would definitely have to take a look back at my observing reports.

Syed do you know anyone else in the localDetroit suberb area that has the same Gen 3 eyepiece that we may be able to convince to use with my Dek II binoviewers and two dual power switches and 100mm right angled binoculars?
I would be interested how they work with all none powerswith options with the A45mm Multipurpose OCS. It would need a 2" H-alpha filter which I don't have (but I do have the 2" diagonal for my ST80 finder). If you have a 2" focuser on your 120mm we could use that also.

P.S. I have 3 OCSs but the Multipurpose is the widest TFOV and also widest aperture 45mm vs 38mm for the Newtonian and Multiplier OCSs. Plus we will be wanting to spend time looking at objects and not so much time switching equipment. But I really have 3x3x3=27 power and TFOV options per eyepiece pair.

Ken

Edited by faackanders2, 22 March 2018 - 07:06 PM.


#84 Jeff Morgan

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Posted 22 March 2018 - 10:21 PM

Thinking back to last year, I'm sure I've checked out the Dumbbell and was thoroughly impressed but as for any others, I would definitely have to take a look back at my observing reports. 

 

When you use a H-alpha filter you get the the portions of the nebula oriented at 90 degrees to the traditional dumbbell lobes. And those extensions are bright. Perhaps as bright as the traditional nebula. It looks something like this APOD image (in monochrome of course):

 

https://apod.nasa.go...d/ap080626.html



#85 The Ardent

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Posted 22 March 2018 - 11:36 PM

Unfiltered and H-alpha

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#86 faackanders2

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Posted 23 March 2018 - 05:29 AM

Syed do you know anyone else in the localDetroit suberb area that has the same Gen 3 eyepiece that we may be able to convince to use with my Dek II binoviewers and two dual power switches and 100mm right angled binoculars?
I would be interested how they work with all none powerswith options with the A45mm Multipurpose OCS. It would need a 2" H-alpha filter which I don't have (but I do have the 2" diagonal for my ST80 finder). If you have a 2" focuser on your 120mm we could use that also.

P.S. I have 3 OCSs but the Multipurpose is the widest TFOV and also widest aperture 45mm vs 38mm for the Newtonian and Multiplier OCSs. Plus we will be wanting to spend time looking at objects and not so much time switching equipment. But I really have 3x3x3=27 power and TFOV options per eyepiece pair.

Ken

I ordered a 2" Lumcon H-Alpha "nighttime photographic" filter ($76 no shipping), so I would have one for my 2" binoviewers and it may work on M42 Orion and/or M8 Lagoon with single eyepiece visually, although I doubt it would work on California or Cacoon (since I have not seen Cacoon with H-Beta on my 17.5" f4.1 visually yet).
Hopefully we luck out being able to find two others with NV Gen 3 to try with my Denk II binoviewers or 90 deg 100mm binos in the Detroit suberb area and/or GLSZ 2018.

Edited by faackanders2, 23 March 2018 - 05:30 AM.


#87 faackanders2

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Posted 23 March 2018 - 05:33 AM

And again, this is not at time exposure. While it does take dark skies to see the full nebula shown in the above picture, you can easily see all of this in real time.   The amount of nebula visible in the Milky Way under dark skies totally redefined my understanding of the galaxy we live in.
 
Frankly, galaxies are boring to me now.   The most astonishing DSO of all time to me is the Milky Way at 1x.  It is staggringly rich with gas clouds and star concentrations.   
 
(The other appeal of 1x and 3x is that there is no setup or take down time, and no mount required.    I can observe while taking out the trash at night.  I used to tell people not to be surprised if low power observing became their most used method of viewing).

For galaxies has anyone tried NV Eyepiece with DGC Galaxy Contrast Enhancement (GCE) filter?

#88 Sarkikos

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Posted 23 March 2018 - 05:49 AM

Given the large, fixed initial outlay that image intensifiers require, where do the experts think that the sweet spot for getting into NV is for newbies like me who are progressing in the hobby? Jeff and Eddgie seem like they've had one of everything before, but with your experience, where do you see image intensification in the cost-benefit landscape for new hobbyists?

Not just for newbies but for the vast majority of amateur astronomers, we're stilling waiting for that sweet spot for getting into NV.

 

Mike


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#89 Sarkikos

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Posted 23 March 2018 - 05:56 AM

I tried an I3 for my 22". It did very little for galaxies, my main observing interest, and ruined the night vision in my observing eye. I returned it.

I'm also concerned that NV would ruin night vision for other observers in the field who are still using conventional equipment.  The NVers always seem to downplay this possibility.  But at a dark site, even a small though bright red light can ruin it for those who are trying to maximize their dark adaptation.  An eyepiece blasting out white light - or bright green light - would not be welcome. We have enough trouble already with the APers and their laptops.   And no, I don't expect all the other observers in the field to convert to NV.

 

Mike


Edited by Sarkikos, 23 March 2018 - 05:58 AM.

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#90 turtle86

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Posted 23 March 2018 - 07:05 AM

I'm also concerned that NV would ruin night vision for other observers in the field who are still using conventional equipment.  The NVers always seem to downplay this possibility.  But at a dark site, even a small though bright red light can ruin it for those who are trying to maximize their dark adaptation.  An eyepiece blasting out white light - or bright green light - would not be welcome. We have enough trouble already with the APers and their laptops.   And no, I don't expect all the other observers in the field to convert to NV.

 

Mike

 

I'm a little concerned about that too. The last thing I want to see at a dark site, especially after driving 2+ hours to get away from light pollution, is more light pollution.  On the other hand, most imagers I see now are pretty good about shielding light from their laptops, so I'm cautiously optimistic that those with NV will do the same.

 

I mostly observe galaxies, and I get the sense from most of the posts that NV won't help too much with that, just as galaxy filters apparently don't help much either.  Plus, as Schneor says, using one will ruin your night vision. So for now I'm sticking with my tried and true formula of aperture and dark skies, at least for galaxies. 

 

However, I do see myself going into NV in the near future for backyard observing at least, as NV unquestionably does a great job on many nebulas, and will cut through a lot of the light pollution so I'll be able to see from my backyard many things I could never see before...


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#91 Eddgie

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Posted 23 March 2018 - 08:42 AM

For NV, dark adaptation does not matter at all. 

For going back and forth, use one eye for NV and the other for conventional.   Just pick the eye that works best for conventional because the NV eye does not work hard at all.

 

 

Not just for newbies but for the vast majority of amateur astronomers, we're stilling waiting for that sweet spot for getting into NV.

 

Mike

Prices for used PVS-7s are very reasonable.   

Also, you can build up you own system for considerable savings.   It is easy to do.

 

A good new (still in the box) later model MX 10130 (PVS-7) tube can often be found on Ebay for as little as $1000 and you can build a PVS-7 from parts for $500 (patience...)

 

One member just posted pictures he took though is parted together Mod 3 C using a very nice 10160 type tube (the type used in PVS-14 ) that he said he got at a considerable saving because it has a few blemishes very near the outside edge.  Blemishes near the edge go almost unnoticed in normal viewing. 

 

I bought a used Micro monocular with an outstanding MX 10160 C/UV (which is the tube used in aviator NV and is ultra sharp) for well under $2000.  I love using this tube.

 

Also, I own both green and WP.  While I understand why many like WP, in use, the P43 green phosphor is quite outstanding.  Your eye settles in and the view becomes monochromatic in the sense that your brain simply does not notice the color.  I think the P43 aviator tube presents sharper stars than the WP tubes, and can have better high light contrast, which can improve the detail on bright nebula.   Orion is fantastic in the green tubes.   

 

The thing though is that prices are unlikely to come down much and if you are inclinded to do even a modest amount of research and are patient enough to wait for good deals, you can build up an excellent NV device for astronomy for under $2K.



#92 Doug Culbertson

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Posted 23 March 2018 - 08:57 AM

For NV, dark adaptation does not matter at all. 

For going back and forth, use one eye for NV and the other for conventional.   Just pick the eye that works best for conventional because the NV eye does not work hard at all.

 

 

Prices for used PVS-7s are very reasonable.   

Also, you can build up you own system for considerable savings.   It is easy to do.

 

A good new (still in the box) later model MX 10130 (PVS-7) tube can often be found on Ebay for as little as $1000 and you can build a PVS-7 from parts for $500 (patience...)

 

One member just posted pictures he took though is parted together Mod 3 C using a very nice 10160 type tube (the type used in PVS-14 ) that he said he got at a considerable saving because it has a few blemishes very near the outside edge.  Blemishes near the edge go almost unnoticed in normal viewing. 

 

I bought a used Micro monocular with an outstanding MX 10160 C/UV (which is the tube used in aviator NV and is ultra sharp) for well under $2000.  I love using this tube.

 

Also, I own both green and WP.  While I understand why many like WP, in use, the P43 green phosphor is quite outstanding.  Your eye settles in and the view becomes monochromatic in the sense that your brain simply does not notice the color.  I think the P43 aviator tube presents sharper stars than the WP tubes, and can have better high light contrast, which can improve the detail on bright nebula.   Orion is fantastic in the green tubes.   

 

The thing though is that prices are unlikely to come down much and if you are inclinded to do even a modest amount of research and are patient enough to wait for good deals, you can build up an excellent NV device for astronomy for under $2K.

 

To add to what Eddgie said, and for the umpteenth time that I have said this, you could be standing three feet away from me and never know that I was using a NV device in my telescope. These are not like LCD screens that the Mallincam guys are using, and they do not throw out some kind of light dome around the telescope. Seriously, worrying about NV causing some kind of light pollution at your dark site is not a valid concern.

 

Also, just like with conventional observing, NV is even better at a dark site than it is under light pollution.


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#93 JakeJ

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Posted 23 March 2018 - 09:02 AM

Unfiltered and H-alpha

These photos of M27 show how NV has always looked to me - grainy, green, haloed stars, and low resolution.  Also I see quite a bit of coma, not sure if from the scope or device.

 

Color me not impressed with this image - I can see m27 better/more detailed than that with a UHC filter and C8 from my severely light polluted back yard in Long Beach, and without all the ugliness.  


Edited by JakeJ, 23 March 2018 - 09:06 AM.


#94 bobhen

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Posted 23 March 2018 - 09:08 AM

I'm a little concerned about that too. The last thing I want to see at a dark site, especially after driving 2+ hours to get away from light pollution, is more light pollution.  On the other hand, most imagers I see now are pretty good about shielding light from their laptops, so I'm cautiously optimistic that those with NV will do the same.

 

I mostly observe galaxies, and I get the sense from most of the posts that NV won't help too much with that, just as galaxy filters apparently don't help much either.  Plus, as Schneor says, using one will ruin your night vision. So for now I'm sticking with my tried and true formula of aperture and dark skies, at least for galaxies. 

 

However, I do see myself going into NV in the near future for backyard observing at least, as NV unquestionably does a great job on many nebulas, and will cut through a lot of the light pollution so I'll be able to see from my backyard many things I could never see before...

You need to look directly into an image intensifier (like you would an eyepiece) for it to impact your vision. NV will not ruin other nearby observers’ dark adaption.

 

NV will impact (however it’s nowhere near as drastic as say looking at a distant computer screen) your own dark adaption but only if you go back and forth between NV and non-assisted viewing. And you could always plan a session around knowing that at some point you will be using NV. Of course, if you are using NV for all of its advantages, there is not much point in going back and forth. I haven’t used a conventional eyepiece (for deep sky observing) in the 2-years since I’ve been using NV.

 

With NV, a dark sky is nowhere near as important as it is with non-assisted viewing. Using NV from Philadelphia, PA I can see Barnard’s loop and the Horsehead Nebula so traveling to a dark sky just does not have the attraction that it would if I could not see these objects from home.

 

Galaxies through any scope will be improved with NV. And, as with most objects, some galaxies are improved more than others. But you will definitely have an easier time seeing and locating galaxies using NV than without. For capturing detail and with their long integrations, NV cannot compete with CCD or even astro-video, but then neither can a large Dobsonian. However, NV will increase the light gathering capability of your current telescope. So just as going from an 8-inch mirror to a 16-inch mirror makes galaxies easier to see and locate, NV will do the same. NV just won’t show the same level of detail that a 40-second CCD image will. NV is not an imaging pursuit. NV is a real-time, visual observing pursuit.

 

In mild or heavy light pollution, the benefit of NV (with filters) on galaxies is even more pronounced, where larger aperture used with ineffective filters is just not that beneficial.

 

If you want more light-gathering capability and more contrast (especially in mild and heavy light pollution) but don’t want to double the size of your telescope and then schlep that large scope to a dark sky, NV is a viable alternative with a lot of advantages. Is NV perfect, no, but then neither is owning a large Dobsonian. People have put up with the disadvantages of the big Dobsonian/dark sky travel strategy because there was no alternative. NV, however, offers a viable and practical alternative solution to the problems inherent in that big Dob/dark sky strategy.

 

Bob


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#95 bobhen

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Posted 23 March 2018 - 09:13 AM

These photos of M27 show how NV has always looked to me - grainy, green, haloed stars, and low resolution.  Also I see quite a bit of coma, not sure if from the scope or device.

 

Color me not impressed with this image - I can see m27 better/more detailed than that with a UHC filter and C8 from my severely light polluted back yard in Long Beach, and without all the ugliness.  

How about theses images?

 

HERE is a link.

 

Bob



#96 Jeff Morgan

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Posted 23 March 2018 - 09:22 AM

For galaxies has anyone tried NV Eyepiece with DGC Galaxy Contrast Enhancement (GCE) filter?

 

Just ordered the GCE this morning. I'll be comparing it to the Astronomiks CLS Visual.

 

The transmission curves appear similar, the Astronomiks being perhaps a bit "tighter". It also appears to have better transmission at 750nm. Unfortunately, that is the extreme edge of the graph.

 

http://www.astronomi...cls-filter.html

http://nebula.wsimg....0&alloworigin=1

 

It would be nice have the data out to 900nm since NV is quite responsive that far into the NIR.

 

I suspect which one is "best" will be dependent upon local light pollution conditions.



#97 Jeff Morgan

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Posted 23 March 2018 - 09:31 AM

Given the large, fixed initial outlay that image intensifiers require, where do the experts think that the sweet spot for getting into NV is for newbies like me who are progressing in the hobby? Jeff and Eddgie seem like they've had one of everything before, but with your experience, where do you see image intensification in the cost-benefit landscape for new hobbyists?

I missed this post and saw it re-quoted later and thought a small "correction" was in order.

 

For the record, I have only owned one NV device - the Mod 3C with a L3 filmless white phosphor tube which I have been using extensively in various configurations (1x, afocal, telephoto, eyepiece for multiple telescopes) since August 2016.

 

Eddgie has broader experience across multiple NV devices than I do.



#98 Jeff Morgan

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Posted 23 March 2018 - 09:36 AM

I'm also concerned that NV would ruin night vision for other observers in the field who are still using conventional equipment.  The NVers always seem to downplay this possibility.  But at a dark site, even a small though bright red light can ruin it for those who are trying to maximize their dark adaptation.  An eyepiece blasting out white light - or bright green light - would not be welcome. We have enough trouble already with the APers and their laptops.   And no, I don't expect all the other observers in the field to convert to NV.

 

Mike

 

Easy fix - You are in control of your own session. Save the NV viewing for the end of the session.

 

But seriously, if you are going after "limit" observations of faint fuzzies do you grab the conventional eyepiece, or one that enables your telescope to reach 2+ magnitudes deeper?


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#99 Jeff Morgan

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Posted 23 March 2018 - 10:09 AM

These photos of M27 show how NV has always looked to me - grainy, green, haloed stars, and low resolution.  Also I see quite a bit of coma, not sure if from the scope or device.

 

Color me not impressed with this image - I can see m27 better/more detailed than that with a UHC filter and C8 from my severely light polluted back yard in Long Beach, and without all the ugliness.  

 

Try hand-holding a cell phone up to your favorite conventional eyepiece and taking a snapshot of M27 and get back to us with that result.

 

The guys buying the phone brackets, having the newer phones, and using apps like NightCap are getting some neat results. All kinds of great cell phone snapshots popping up lately. Like these:

 

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

https://www.cloudyni...-pds/?p=8468531

 

Of course one sees more visually. The story is not that these captures are "just what you see" visually.

 

The story is that the devices can make a DSO bright enough to be captured with a cell phone camera! (The secondary story is that NV is catching on.)

 

Making objects brighter is why we buy ever-larger, expensive, and heavy telescopes, isn't it?

 

The idea that you will be seeing more/better/deeper with a conventional eyepiece with a UHC filter in a C-8 will be pretty funny to those that have tried both lol.gif


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#100 turtle86

turtle86

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Posted 23 March 2018 - 10:12 AM

You need to look directly into an image intensifier (like you would an eyepiece) for it to impact your vision. NV will not ruin other nearby observers’ dark adaption.

 

NV will impact (however it’s nowhere near as drastic as say looking at a distant computer screen) your own dark adaption but only if you go back and forth between NV and non-assisted viewing. And you could always plan a session around knowing that at some point you will be using NV. Of course, if you are using NV for all of its advantages, there is not much point in going back and forth. I haven’t used a conventional eyepiece (for deep sky observing) in the 2-years since I’ve been using NV.

 

With NV, a dark sky is nowhere near as important as it is with non-assisted viewing. Using NV from Philadelphia, PA I can see Barnard’s loop and the Horsehead Nebula so traveling to a dark sky just does not have the attraction that it would if I could not see these objects from home.

 

Galaxies through any scope will be improved with NV. And, as with most objects, some galaxies are improved more than others. But you will definitely have an easier time seeing and locating galaxies using NV than without. For capturing detail and with their long integrations, NV cannot compete with CCD or even astro-video, but then neither can a large Dobsonian. However, NV will increase the light gathering capability of your current telescope. So just as going from an 8-inch mirror to a 16-inch mirror makes galaxies easier to see and locate, NV will do the same. NV just won’t show the same level of detail that a 40-second CCD image will. NV is not an imaging pursuit. NV is a real-time, visual observing pursuit.

 

In mild or heavy light pollution, the benefit of NV (with filters) on galaxies is even more pronounced, where larger aperture used with ineffective filters is just not that beneficial.

 

If you want more light-gathering capability and more contrast (especially in mild and heavy light pollution) but don’t want to double the size of your telescope and then schlep that large scope to a dark sky, NV is a viable alternative with a lot of advantages. Is NV perfect, no, but then neither is owning a large Dobsonian. People have put up with the disadvantages of the big Dobsonian/dark sky travel strategy because there was no alternative. NV, however, offers a viable and practical alternative solution to the problems inherent in that big Dob/dark sky strategy.

 

Bob

 

Bob, thanks so much for your post.  I'll always enjoy observing the old-fashioned way, but I definitely see the benefit of NV, especially from my light-polluted backyard.  I also see the benefit of NV at my dark site for going deeper. As you suggest, I can avoid losing my dark adaptation by not going back and forth and simply planning when I'd be using NV.  I already do that anyway for planets, since I've found that you really *don't* want to be dark adapted for planetary viewing. Last week in fact I saved Jupiter for last at 3 am, after completing my DSO viewing. 




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