"Dennis Persyk" wrote in message
om...
"Richard Crisp" wrote in message
.com...
"Dennis Persyk" wrote in message
om...
IC405 is an emission nebula glowing richly in red H-alpha light. By
employing a selective spike filter that passes only the H-a emission
line, one can block out light pollution and even the effects of a
nearby full moon.

You may view filtered and non-filtered views of IC405 that illustrate
the unique properties of the H-a filter at
http://home.att.net/~dpersyk/new.htm

I hope you will take a look and find the comparison interesting.


Ahah! you have stumbled onto my secrets, Dennis!

I love to image faint nebulae during full moons with emission line
filters.

Here's a 12.66mag planetary shot with Ha, [OIII] and [SII]. This was
taken
under a FULL MOON.

http://www.rdcrisp.darkhorizons.org/pk164_page.htm

here are some IC405 shots taken with various emission line filters.
Unfortunately they are rather undersampled.

http://www.rdcrisp.darkhorizons.org/ic405_Ha_page.htm

Keep up that good Ha imaging. I suggest you get an [OIII] filter too.
That
camera of yours will work even better with [OIII] because the quantum
efficiency is better at that wavelength (500.7nm).

Best regards
Richard

Richard, your wide field images are out of this world! And yes, the
wonders of the narrow band filter seem to be a well-kept secret. The
H-alpha filter effectively doubles the number of nights per month I
can image DSOs. Unfortunately, doubling a small number produces
another small number.

I hope you will share your list of targets for H-a and O-III imaging
with me. I have not been successful in finding a comprehensive list of
these guys – another seemingly well-kept secret.


I don't have a comprehensive list, but I do have a log of the ones I've
imaged that way in the past few months.

Have a look at my reverse chronological list here. Nearly every one I have
imaged with the emission line filters is there.

http://www.rdcrisp.darkhorizons.org/New_Images_page.htm

For me this is like a voyage of discovery: most of the time I've not seen
the various nebulae imaged in any way other than LRGB or maybe Ha.


Best wishes
Richard