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Equipment Discussions >> Video and Electronically Assisted Astronomy

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jdbastro
sage


Reged: 08/18/07

Loc: W. Coast
Nebula Pics thru Image Intensifier
      #5622021 - 01/14/13 01:11 AM Attachment (57 downloads)

This is my first foray into the world of imaging off of a Gen3 Image intensifier. This shot was taken thru a Mewlon 250 scope in heavily light polluted skies. A 12nm narrow band H-alpha filter was attached to the input end of the intensifier.
Here is the HorseHead Nebula shot in 8 seconds:


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jdbastro
sage


Reged: 08/18/07

Loc: W. Coast
Re: Nebula Pics thru Image Intensifier new [Re: jdbastro]
      #5622023 - 01/14/13 01:12 AM Attachment (48 downloads)

Here is a shot of the flame (8 second exposure):

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jdbastro
sage


Reged: 08/18/07

Loc: W. Coast
Re: Nebula Pics thru Image Intensifier new [Re: jdbastro]
      #5622026 - 01/14/13 01:13 AM Attachment (41 downloads)

This is the crab nebula (8 second exposure):

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jdbastro
sage


Reged: 08/18/07

Loc: W. Coast
Re: Nebula Pics thru Image Intensifier new [Re: jdbastro]
      #5622029 - 01/14/13 01:14 AM Attachment (45 downloads)

Finally everyone's favorite, M42 (in about 1 second):

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jdbastro
sage


Reged: 08/18/07

Loc: W. Coast
Re: Nebula Pics thru Image Intensifier new [Re: jdbastro]
      #5622032 - 01/14/13 01:16 AM

The camera used was a Panasonic Lumix G5 with a 20mm f1.7 lens looking into the eyepiece of the image intensifier unit (a Micro Monocular) - afocal photography.

Cheers.


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nytecam
Postmaster


Reged: 08/20/05

Loc: London UK
Re: Nebula Pics thru Image Intensifier new [Re: jdbastro]
      #5622125 - 01/14/13 04:59 AM

Quote:

The camera used was a Panasonic Lumix G5 with a 20mm f1.7 lens looking into the eyepiece of the image intensifier unit (a Micro Monocular) - afocal photography.
Cheers.


These are great images especially liked the crisp Horsehead and the Crab M1 - well done and more please

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Lightning
sage


Reged: 07/04/10

Loc: Canberra, Australia
Re: Nebula Pics thru Image Intensifier new [Re: nytecam]
      #5622157 - 01/14/13 05:52 AM

They are really quite remarkable. Really ghostly in appearance. Have you tried taking a number of pics and stacking them in DeepSkyStacker or such?

Great work, cheers for sharing,
Cam


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highfnum
Carpal Tunnel
*****

Reged: 09/06/06

Loc: NE USA
Re: Nebula Pics thru Image Intensifier new [Re: Lightning]
      #5622222 - 01/14/13 07:51 AM

great job

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StarStuff1
Post Laureate
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Reged: 04/01/07

Loc: South of the Mason-Dixon Line
Re: Nebula Pics thru Image Intensifier new [Re: highfnum]
      #5622237 - 01/14/13 08:09 AM

Excellent!! I especially like the details in the Crab.

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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Nebula Pics thru Image Intensifier new [Re: StarStuff1]
      #5622308 - 01/14/13 09:20 AM

very interesting . Not knowing much about gen 3 intensifiers, are those many bright little dots stars or intensifier noise , and if they are at least some of them noise, how can it be reduced?

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GlennLeDrew
Postmaster
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Nebula Pics thru Image Intensifier new [Re: mattflastro]
      #5622337 - 01/14/13 09:40 AM

The multitudinous specks are indeed noise, or scintillation, as it's called with intensifiers. Stacking a number of images would significantly reduce their impact.

Another strategy would be to use a scope working at a faster f/ratio, and/or employ a focal reducer. This would form an image having higher surface brightness, thereby increasing signal to noise. The result would be a smoother, 'lusher' image, especially if the gain can also be dialed down.


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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Nebula Pics thru Image Intensifier new [Re: GlennLeDrew]
      #5622345 - 01/14/13 09:46 AM

Quote:

The multitudinous specks are indeed noise, or scintillation, as it's called with intensifiers. Stacking a number of images would significantly reduce their impact.

Another strategy would be to use a scope working at a faster f/ratio, and/or employ a focal reducer. This would form an image having higher surface brightness, thereby increasing signal to noise. The result would be a smoother, 'lusher' image, especially if the gain can also be dialed down.




I wonder what's the duration of each of these scintillations . How fast of a frame rate could be used , assuming I had a camera capable of let's say 500 -1000 fps and stacked 5-20 frames on the fly , would it reduce them significantly? That way the device would still send live video but hopefully less noisy ? Increasing sgnal to noise by reducing noise is more work but addresses the problem without saturating the highlights .


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dtripz
member
*****

Reged: 04/01/08

Loc: Brooklyn NY
Re: Nebula Pics thru Image Intensifier new [Re: mattflastro]
      #5622392 - 01/14/13 10:12 AM

Well done! I'd love to see some more if you have. Out of curiosity how do these compare with looking through the tube with your own eye, also what light pollution zone are you in?

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StarStuff1
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Reged: 04/01/07

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Re: Nebula Pics thru Image Intensifier new [Re: dtripz]
      #5622485 - 01/14/13 11:18 AM

Generally speaking, the stronger the filtration the more the scintillation. My 12nm Ha filter shows a lot, less in darker skies. My Orion SkyGlow photographic and my Lumicon Deep Sky show noticeably less, even in more LP environs. All experiences with naked eye viewing, not photographically.

BTW Glenn, my IIE has automatic gain and I think most, if not all others, are the same. So gain is not normally adjustable on IIEs. Think of looking over the battlefield and an artillery burst happens nearby. Self survival for the image intensifier tube.

Agree with dtripz, more pics if available.


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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Nebula Pics thru Image Intensifier new [Re: StarStuff1]
      #5622604 - 01/14/13 12:37 PM

Quote:

Generally speaking, the stronger the filtration the more the scintillation. My 12nm Ha filter shows a lot, less in darker skies. My Orion SkyGlow photographic and my Lumicon Deep Sky show noticeably less, even in more LP environs. All experiences with naked eye viewing, not photographically.

BTW Glenn, my IIE has automatic gain and I think most, if not all others, are the same. So gain is not normally adjustable on IIEs. Think of looking over the battlefield and an artillery burst happens nearby. Self survival for the image intensifier tube.

Agree with dtripz, more pics if available.




Is this effect of the stronger the filtration the stronger the scintillation due to the skyglow being amplified and becoming bright enough to hide the scintillation ?


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StarStuff1
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Reged: 04/01/07

Loc: South of the Mason-Dixon Line
Re: Nebula Pics thru Image Intensifier new [Re: mattflastro]
      #5622908 - 01/14/13 03:40 PM

If I understand your question, yes. When using the IIE in a small optic for simple night vision in the neighborhood and with no filtration there is little or no scintillation. Very smooth.

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highfnum
Carpal Tunnel
*****

Reged: 09/06/06

Loc: NE USA
Re: Nebula Pics thru Image Intensifier new [Re: StarStuff1]
      #5622914 - 01/14/13 03:43 PM

filters cause a certain amount of photon starvation
that forces gain to increase
more gain more noise

but for Ha it still worth it
you get more than you lose


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PEterW
professor emeritus


Reged: 01/02/06

Loc: SW London, UK
Re: Nebula Pics thru Image Intensifier new [Re: highfnum]
      #5622977 - 01/14/13 04:15 PM

The figure of merit for intensifiers is equivalent background illumination, essentially the brightness of the output with no input, which your deep sky objects need to be able to poke through. You also want to be below f4 as well, the faster the better.
Be interested in the visibility of nebulae and amount of scintillation with transparency and stray light. I assume nebulae disappear with the other light pollution filters, brighter sky and less scintillation though. I get the same with my rg630 light pollution elimination filter, have to try my CLS filter. So the intensifier equivalent of averted vision is mentally averaging the scintillation. How do things get as the bandwidth drops, thought 10nm was about optimum?

Cheers
PeterW


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highfnum
Carpal Tunnel
*****

Reged: 09/06/06

Loc: NE USA
Re: Nebula Pics thru Image Intensifier new [Re: PEterW]
      #5623019 - 01/14/13 04:30 PM

if you can do a series of shots and stack you reduce noise
I did a test a while back
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5229288/page...


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GlennLeDrew
Postmaster
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Nebula Pics thru Image Intensifier new [Re: highfnum]
      #5623549 - 01/14/13 10:20 PM

The more aggressive the filtration, the more sky glow is reduced, and the more prominently the scintillation presents itself against the darker image. This is why a faster f/ratio is required. For example, an f/8 scope equipped with a 0.5X focal reducer works at f/4. Image surface brightness scales as the inverse of the f/ratio squared, and so the f/4 image equals (8 / 4)^2, or 4 times brighter.

Trying to reduce scintillation in images by shortening the exposure time may not be of significant help. But given that the noise in the intensifier's output is already high, you can crank up your camera's ISO setting without fear of that noise source being too detrimental. Then it's a matter of selecting an exposure which reasonably well fills in the darker end (left side, by convention) of the histogram.

Ultimately, as Hifnum's linked-to post showed via some example images, stacking is the best bet for a rather more nicely smooth result.


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