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Dennis Persyk
February 20th 04, 09:45 PM
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.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL

Richard Crisp
February 21st 04, 12:33 AM
"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

Dennis Persyk
February 21st 04, 03:51 PM
"Richard Crisp" > wrote in message >...
> "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.

Clear skies,

Dennis

Richard Crisp
February 21st 04, 04:00 PM
"Dennis Persyk" > wrote in message
om...
> "Richard Crisp" > wrote in message
>...
> > "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