Theres more to it than "light amplification." The NV images are indeed brighter (people record them with their iPhones, etc.), but I am not sure there is significantly more information. The NV system adds shot noise, dark current, scintillation, etc. that weren't there before. So it's not just 1000x more photons or whatever the number is.
The videos in post #5 and #6 are something to think about, at least for me. I am left feeling like I've had a similar or better views visually with an 8" to 12" plus an OIII filter. Albeit from some dark location. Certainly to get these views from the city is impressive. And yes Horse Head in a TV85 is fantastic -- and maybe 5 or 6 other H-alpha objects.
I guess what I'd really like to see is the coma galaxy cluster in real-time view in that TV85 + NV or something like that... Hmmm...
This has been interesting! Thanks!
First, videos are NOT a good representation of what is seen in the eyepiece. They magnify scintillation and over emphasize the green tint – and by a lot. The still images are a much closer representation.
It’s not just the increased brightness it is also (with the addition of strong filters) the huge increase in contrast that makes some of these impossible observations possible.
With an intensifier you have so much light that you can throw some away and take advantage of these strong filters.
For example: not only will you see the Veil Nebula easily but you will see the faint center section and you will observe the photo-like streamers in the brighter arc – even in small telescopes like a 4” refractor. With my 210mm reflector these streamers look detailed and photographic.
You won’t get image scale out of a TV 85 or a 4” refractor etc. they are used for low power, wide field observing, just like with unassisted observing.
For galaxies and small objects, image scale is needed, something in the range of 1,500mm to 3,000mm FL depending on the object.
I can only give you a few examples: for years I owned a 15” reflector and never saw galaxy 891 (or the Horse Head or the Flame Nebula for that matter) from my light polluted location. I have seen 891 with a 120mm refractor and the intensifier – its dim but observable – even including its pencil-line dark lane.
Faint globular clusters that are unresolved (and it doesn’t matter how large your telescope is, some globulars will always be unresolved) these become resolved and actually become more unique individuals in appearance because the fainter or invisible stars become visible.
I was out last night for about an hour and a half with my 4” F5 refractor working at F3.5 and the intensifier
There was a touch of moisture in the sky.
The location was about 8-10 miles outside of Philadelphia in absolutely horrendous light pollution with neighbor’s lights on and a few passing cars. The only place worse to observe would be in the center of Philadelphia itself!
Here is my list of objects observed...
Detached nebula: N6559, IC-1274, and IC-4681
The faint connecting bridge from M20 to M8 was also seen.
6888 Crescent Nebula
North American Nebula
Y Sadr Complex: IC-1311, IC-1318, 6914, IC-4996, IC-5068, SH2-112, and more
Lots of Dark Nebula Near the Galactic Center:
The big 4 summer nebula were near photographic (and in some ways better) in appearance, resembling 5 to 10-second short exposure images
The dark nebulas superimposed over the bright galactic center were easy, hard-edged and very impressive. These dark nebula superimposed over the bright, rich, star-filled galactic core were so impressive that I mumbled out an audible “wow” at the eyepiece.
Cygnus was so thick with nebula that the nebulas resembled faint clouds.
Seeing a patch of nebula near M27 that most observers don’t even know exists also gives some idea of what can be seen.
Again, from near Philadelphia (so no travel), from my front yard, with a 4-inch refractor on a simple alt/az mount. I didn’t even bring out a chair.
Edited by bobhen, 25 August 2019 - 08:01 AM.