Nebula magnet anyone?

[PeterW]

Ebay head up from another forum.. http://www.cloudynights.com/topic/492020-image-intensifying-or-night-vision-device/#entry6467628 add to a suitable housing, add narrow hydrogen alpha filter and bingo, "faint nebulae" can become visible. Welcome to "the green side"...

Cheers

PeterW

[jetstream]

Ok I have to ask, do you use these for visual? if so what is the configuration?

[PeterW]

Yes. Scope-filters-magic bit-eyepiece bit- eyeball. Red glass can help filter out light pollution, hydrogen alpha filters for nebulae. Resolves globulars nicely too.

PeterW

[jetstream]

So an eyepiece is used with the image intensifier? I read over on the CN link that a Ha filter is used with these, does it matter where it goes? before the intensifier I presume? This interests me.

[PeterW]

Filter before everything, you need to select which photons you want to intensify. If you don't like the bright green output you can put an orange filter in the eyepiece to reduce the brightness of the image, reduces the damage to your night vision. You'll find that averted vision is still a useful skill to hunt for the faintest stuff. The "eyepiece" is part of the monocular that magnifies the intensifier screen for viewing... Not something you have in your eyepiece case or something you change. You could probably do a DIY job, I know some people who could help.

PeterW

[jetstream]

Do different monoculars offer different mags? What is a typical "focal length " that is given in order to figure mag out? ie mag in my 1200mm fl dob.

One more question...is it beneficial with one of these to run it through larger aperture? I just spent a wad of cash so this set up will have to wait, but I will try to get a handle on it first.

Thanks for the info Pete.

[PeterW]

The monocular eyepiece just magnifies the output screen and projects it into your eye. No point in zooming with that. For stars aperture will affect how faint you can go, for nebulae it is the focal ratio. You want FAST, the focal length just changes the field of view. So big aperure is not necessary for big nebulae, though it will help make galaxies appear larger. If people were sellin f3 dobsonians more I would be interested, though very fast affects the oerformance of narrowband filters. I believe that 27mm is the effective focal length... It is for camera lenses. Many nebulae are larger than the full moon. Go back through the cloudynights posts as they retry much cover the questions. Happy to answer more if I can

Cheers

Peter

[jetstream]

Awesome Pete! I am a nebula hunter and travel to dark sites quite a bit. I see that what we are after is FOV here, I wonder what the clear aperture of the image intensifier is, the most I can get with my 2" focuser is about 2 deg TFOV or so. I view the great IC1318 (shades) from my dark sites and would love to really see this huge neb better.

Why Ha to view? Instead of OIII or Hb? is it because of some interaction with the intensifier? How does the Veil show?

[PeterW]

Ic1318 is a good region, but the heart and soul are better and barnards loop and angelfish nebulae are good to see too.

Cheers

Peter