ASTRO: Initial experiments with continuum subtraction of Halpha images

I took this Halpha and Red Continuum data in M33 back in early Jan

I processed it a bit differently today, normalizing the star intensities
with a global scaling of the continuum data, and then made this web page

at the very bottom is a side by side comparison of plain Halpha, Continuum
Subtracted Halpha and the Red Continuum

There certainly are places where regions were interconnected by "nebulosity"
that no longer are once the continuum subtraction was made.

http://www.narrowbandimaging.com/con...itial_page.htm

stars are very sensitive to being subtracted and any difference in "shape"
and surface profile may result in artifacts in the subtracted result.
Saturating them should be strictly avoided at all times.

the stars need some work and method tweaking but the nebulosity is
interesting.

one other point is that obviously more exposure time must be logged as well
as additional flats...

Richard,

M33 looks cool without the continuum. Quite a different view to the "normal"
images.

Stefan

"Richard Crisp" schrieb im Newsbeitrag
. ..
I took this Halpha and Red Continuum data in M33 back in early Jan

I processed it a bit differently today, normalizing the star intensities
with a global scaling of the continuum data, and then made this web page

at the very bottom is a side by side comparison of plain Halpha, Continuum
Subtracted Halpha and the Red Continuum

There certainly are places where regions were interconnected by
"nebulosity" that no longer are once the continuum subtraction was made.

http://www.narrowbandimaging.com/con...itial_page.htm

stars are very sensitive to being subtracted and any difference in "shape"
and surface profile may result in artifacts in the subtracted result.
Saturating them should be strictly avoided at all times.

the stars need some work and method tweaking but the nebulosity is
interesting.

one other point is that obviously more exposure time must be logged as
well as additional flats...

"Stefan Lilge" wrote in message
...
Richard,

M33 looks cool without the continuum. Quite a different view to the
"normal"
images.

thanks for the comment

are you saying that the continuum subtracted version looks good or are you
saying it looks good without the continuum subtraction?

pardon me for being a bit dense :-)

btw if the latter, here is a more detailed view of it:

http://www.narrowbandimaging.com/m33...cs_ha_page.htm



Stefan

"Richard Crisp" schrieb im Newsbeitrag
. ..
I took this Halpha and Red Continuum data in M33 back in early Jan

I processed it a bit differently today, normalizing the star intensities
with a global scaling of the continuum data, and then made this web page

at the very bottom is a side by side comparison of plain Halpha,
Continuum
Subtracted Halpha and the Red Continuum

There certainly are places where regions were interconnected by
"nebulosity" that no longer are once the continuum subtraction was made.

http://www.narrowbandimaging.com/con...itial_page.htm

stars are very sensitive to being subtracted and any difference in
"shape"
and surface profile may result in artifacts in the subtracted result.
Saturating them should be strictly avoided at all times.

the stars need some work and method tweaking but the nebulosity is
interesting.

one other point is that obviously more exposure time must be logged as
well as additional flats...

Richard,

what I meant was that I like the "Halpha only" version of M33. It looks a
bit like parts of the tarantulum nebula.

Stefan

"Richard Crisp" schrieb im Newsbeitrag
et...

"Stefan Lilge" wrote in message
...
Richard,

M33 looks cool without the continuum. Quite a different view to the
"normal"
images.

thanks for the comment

are you saying that the continuum subtracted version looks good or are you
saying it looks good without the continuum subtraction?

pardon me for being a bit dense :-)

btw if the latter, here is a more detailed view of it:

http://www.narrowbandimaging.com/m33...cs_ha_page.htm



Stefan

"Richard Crisp" schrieb im Newsbeitrag
. ..
I took this Halpha and Red Continuum data in M33 back in early Jan

I processed it a bit differently today, normalizing the star intensities
with a global scaling of the continuum data, and then made this web page

at the very bottom is a side by side comparison of plain Halpha,
Continuum
Subtracted Halpha and the Red Continuum

There certainly are places where regions were interconnected by
"nebulosity" that no longer are once the continuum subtraction was made.

http://www.narrowbandimaging.com/con...itial_page.htm

stars are very sensitive to being subtracted and any difference in
"shape"
and surface profile may result in artifacts in the subtracted result.
Saturating them should be strictly avoided at all times.

the stars need some work and method tweaking but the nebulosity is
interesting.

one other point is that obviously more exposure time must be logged as
well as additional flats...