ASTRO: Color Astronomical Imaging with Polarizing Filters

Now that narrowband has become mainstream , it is time to start something
completely new again. Back in late January of this year with the helping
hand of a firm push by my friend Liebrecht Venter, I finally did some
experiments I first discussed with him about two years earlier. This was an
experiment to use polarizing filters (analyzers) to dissect various
astronomical targets in an attempt at making a color image in the event
polarized light was found.

Due to the nature of the Crab Nebula having a pulsar in the middle of it
that emits syncrotron radiation and with such radiation being highly
linearly polarized, the Crab became the first target.

Two types of images were taken: simple Polarigrams that were made from the
output of three polarizers oriented at different angles being assigned to
RGB and another method involving the creation of Stokes parameters with the
various Stokes parameters being assigned to the color channels.

As so often happens in research there was someone down this path before me
and that was David Malin and Professor Pasachoff, who made a Stokes
Parameter image of the Crab nebula in the 90s using film and darkroom
techniques. This is something I learned once I really got deeply involved in
this endeavor.

Apparently Malin and Pasachoff stopped with the Crab and that is truly a
unique target with a very specific mechanism for creating the polarized
radiation. But there are other mechanisms that can result in polarized light
and one of them are dusty regions aligned in strong magnetic fields with
reflection nebulosity. M78 and its neighbors exhibit such polarization.

Additionally protostellar disks may display polarization such as I found in
Hubble's Variable Nebula, the first such image I have seen of that object
or M78

Another fundamentally different mechanism is observed in the outflows from
M82, which I also imaged using the techiques and is another object for which
I have not seen polarization images.

Another object that I have imaged using the technique is NGC7023 which is
another that I haven't seen any such images published before these I am
linking below.

There are a number of other targets that exhibit such polarization and in
time I expect to image a good number of them building instead of an emission
line image catalogue, which I have been building for the past four years
since I began publishing temission line image catalogue (
http://www.narrowbandimaging.com/Tricolor_page.htm ), a catalogue of Stokes
Parameter images of various nebulae and galaxies exhibiting such
polarization.

One very interesting thing about this method is that the filters are cheap.
I used a 50mm round polarizing filter from Edmund Scientific that cost a
whopping $35. So it is actually cheaper to shoot polarization images than
RGB!!! The telescopes used were the Stinger 450 Classical Cassegrain (
http://www.narrowbandimaging.com/Sti...llery_page.htm ), the AP180EDT
f/9 (M78 image) and my Finger Lakes CM10 camera and my Finger Lakes IMG6303
camera all mounted on my AP1200GTO mount(s)

Here is the description page that has images taken using these techiques on
them as well as a paper recently published in "Amateur Astronomy" in the
Fall 2007 issue that I wrote and the original paper I wrote back in early
February of this year when I shot my first round of such images

http://www.narrowbandimaging.com/col...aging_page.htm

I think this is a very new and fresh approach to astroimaging and I know
there are lots of bored imagers out there that simply want to scream if they
see another NGC7000/Pelican in RGB, so here's something new for you guys to
do: brought to you by the same guy that brought you ticolor emission line
imaging about four years ago.

I think the next ground to break may well be out of the visible spectrum
altogether.

Richard

Richard Crisp wrote:

Now that narrowband has become mainstream , it is time to start something
completely new again. Back in late January of this year with the helping
hand of a firm push by my friend Liebrecht Venter, I finally did some
experiments I first discussed with him about two years earlier. This was an
experiment to use polarizing filters (analyzers) to dissect various
astronomical targets in an attempt at making a color image in the event
polarized light was found.

Due to the nature of the Crab Nebula having a pulsar in the middle of it
that emits syncrotron radiation and with such radiation being highly
linearly polarized, the Crab became the first target.

Two types of images were taken: simple Polarigrams that were made from the
output of three polarizers oriented at different angles being assigned to
RGB and another method involving the creation of Stokes parameters with the
various Stokes parameters being assigned to the color channels.

As so often happens in research there was someone down this path before me
and that was David Malin and Professor Pasachoff, who made a Stokes
Parameter image of the Crab nebula in the 90s using film and darkroom
techniques. This is something I learned once I really got deeply involved in
this endeavor.

Apparently Malin and Pasachoff stopped with the Crab and that is truly a
unique target with a very specific mechanism for creating the polarized
radiation. But there are other mechanisms that can result in polarized light
and one of them are dusty regions aligned in strong magnetic fields with
reflection nebulosity. M78 and its neighbors exhibit such polarization.

Additionally protostellar disks may display polarization such as I found in
Hubble's Variable Nebula, the first such image I have seen of that object
or M78

Another fundamentally different mechanism is observed in the outflows from
M82, which I also imaged using the techiques and is another object for which
I have not seen polarization images.

Another object that I have imaged using the technique is NGC7023 which is
another that I haven't seen any such images published before these I am
linking below.

There are a number of other targets that exhibit such polarization and in
time I expect to image a good number of them building instead of an emission
line image catalogue, which I have been building for the past four years
since I began publishing temission line image catalogue (
http://www.narrowbandimaging.com/Tricolor_page.htm ), a catalogue of Stokes
Parameter images of various nebulae and galaxies exhibiting such
polarization.

One very interesting thing about this method is that the filters are cheap.
I used a 50mm round polarizing filter from Edmund Scientific that cost a
whopping $35. So it is actually cheaper to shoot polarization images than
RGB!!! The telescopes used were the Stinger 450 Classical Cassegrain (
http://www.narrowbandimaging.com/Sti...llery_page.htm ), the AP180EDT
f/9 (M78 image) and my Finger Lakes CM10 camera and my Finger Lakes IMG6303
camera all mounted on my AP1200GTO mount(s)

Here is the description page that has images taken using these techiques on
them as well as a paper recently published in "Amateur Astronomy" in the
Fall 2007 issue that I wrote and the original paper I wrote back in early
February of this year when I shot my first round of such images

http://www.narrowbandimaging.com/col...aging_page.htm

I think this is a very new and fresh approach to astroimaging and I know
there are lots of bored imagers out there that simply want to scream if they
see another NGC7000/Pelican in RGB, so here's something new for you guys to
do: brought to you by the same guy that brought you ticolor emission line
imaging about four years ago.

I think the next ground to break may well be out of the visible spectrum
altogether.

Richard

Very interesting. Stefan's polarized light idea was on the right track.
Though that Stokes image of M1 looks like what you see outside a frat
house after too much pizza and beer!

Rick

--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

Great stuff Richard. I doubt that I'll have the patience to use precious
clear skies for similar endeavours, but it's certainly an interesting
approach.

Stefan

"Richard Crisp" schrieb im Newsbeitrag
...
Now that narrowband has become mainstream , it is time to start something
completely new again. Back in late January of this year with the helping
hand of a firm push by my friend Liebrecht Venter, I finally did some
experiments I first discussed with him about two years earlier. This was
an experiment to use polarizing filters (analyzers) to dissect various
astronomical targets in an attempt at making a color image in the event
polarized light was found.

Due to the nature of the Crab Nebula having a pulsar in the middle of it
that emits syncrotron radiation and with such radiation being highly
linearly polarized, the Crab became the first target.

Two types of images were taken: simple Polarigrams that were made from the
output of three polarizers oriented at different angles being assigned to
RGB and another method involving the creation of Stokes parameters with
the various Stokes parameters being assigned to the color channels.

As so often happens in research there was someone down this path before me
and that was David Malin and Professor Pasachoff, who made a Stokes
Parameter image of the Crab nebula in the 90s using film and darkroom
techniques. This is something I learned once I really got deeply involved
in this endeavor.

Apparently Malin and Pasachoff stopped with the Crab and that is truly a
unique target with a very specific mechanism for creating the polarized
radiation. But there are other mechanisms that can result in polarized
light and one of them are dusty regions aligned in strong magnetic fields
with reflection nebulosity. M78 and its neighbors exhibit such
polarization.

Additionally protostellar disks may display polarization such as I found
in Hubble's Variable Nebula, the first such image I have seen of that
object or M78

Another fundamentally different mechanism is observed in the outflows from
M82, which I also imaged using the techiques and is another object for
which I have not seen polarization images.

Another object that I have imaged using the technique is NGC7023 which is
another that I haven't seen any such images published before these I am
linking below.

There are a number of other targets that exhibit such polarization and in
time I expect to image a good number of them building instead of an
emission line image catalogue, which I have been building for the past
four years since I began publishing temission line image catalogue (
http://www.narrowbandimaging.com/Tricolor_page.htm ), a catalogue of
Stokes Parameter images of various nebulae and galaxies exhibiting such
polarization.

One very interesting thing about this method is that the filters are
cheap. I used a 50mm round polarizing filter from Edmund Scientific that
cost a whopping $35. So it is actually cheaper to shoot polarization
images than RGB!!! The telescopes used were the Stinger 450 Classical
Cassegrain ( http://www.narrowbandimaging.com/Sti...llery_page.htm ),
the AP180EDT f/9 (M78 image) and my Finger Lakes CM10 camera and my Finger
Lakes IMG6303 camera all mounted on my AP1200GTO mount(s)

Here is the description page that has images taken using these techiques
on them as well as a paper recently published in "Amateur Astronomy" in
the Fall 2007 issue that I wrote and the original paper I wrote back in
early February of this year when I shot my first round of such images

http://www.narrowbandimaging.com/col...aging_page.htm

I think this is a very new and fresh approach to astroimaging and I know
there are lots of bored imagers out there that simply want to scream if
they see another NGC7000/Pelican in RGB, so here's something new for you
guys to do: brought to you by the same guy that brought you ticolor
emission line imaging about four years ago.

I think the next ground to break may well be out of the visible spectrum
altogether.

Richard

it actually can go pretty fast: the filters are broadband filters so the
exposure times are similar to RGB


"Stefan Lilge" wrote in message
...
Great stuff Richard. I doubt that I'll have the patience to use precious
clear skies for similar endeavours, but it's certainly an interesting
approach.

Stefan

"Richard Crisp" schrieb im Newsbeitrag
...
Now that narrowband has become mainstream , it is time to start something
completely new again. Back in late January of this year with the helping
hand of a firm push by my friend Liebrecht Venter, I finally did some
experiments I first discussed with him about two years earlier. This was
an experiment to use polarizing filters (analyzers) to dissect various
astronomical targets in an attempt at making a color image in the event
polarized light was found.

Due to the nature of the Crab Nebula having a pulsar in the middle of it
that emits syncrotron radiation and with such radiation being highly
linearly polarized, the Crab became the first target.

Two types of images were taken: simple Polarigrams that were made from
the output of three polarizers oriented at different angles being
assigned to RGB and another method involving the creation of Stokes
parameters with the various Stokes parameters being assigned to the color
channels.

As so often happens in research there was someone down this path before
me and that was David Malin and Professor Pasachoff, who made a Stokes
Parameter image of the Crab nebula in the 90s using film and darkroom
techniques. This is something I learned once I really got deeply involved
in this endeavor.

Apparently Malin and Pasachoff stopped with the Crab and that is truly a
unique target with a very specific mechanism for creating the polarized
radiation. But there are other mechanisms that can result in polarized
light and one of them are dusty regions aligned in strong magnetic fields
with reflection nebulosity. M78 and its neighbors exhibit such
polarization.

Additionally protostellar disks may display polarization such as I found
in Hubble's Variable Nebula, the first such image I have seen of that
object or M78

Another fundamentally different mechanism is observed in the outflows
from M82, which I also imaged using the techiques and is another object
for which I have not seen polarization images.

Another object that I have imaged using the technique is NGC7023 which is
another that I haven't seen any such images published before these I am
linking below.

There are a number of other targets that exhibit such polarization and in
time I expect to image a good number of them building instead of an
emission line image catalogue, which I have been building for the past
four years since I began publishing temission line image catalogue (
http://www.narrowbandimaging.com/Tricolor_page.htm ), a catalogue of
Stokes Parameter images of various nebulae and galaxies exhibiting such
polarization.

One very interesting thing about this method is that the filters are
cheap. I used a 50mm round polarizing filter from Edmund Scientific that
cost a whopping $35. So it is actually cheaper to shoot polarization
images than RGB!!! The telescopes used were the Stinger 450 Classical
Cassegrain ( http://www.narrowbandimaging.com/Sti...llery_page.htm ),
the AP180EDT f/9 (M78 image) and my Finger Lakes CM10 camera and my
Finger Lakes IMG6303 camera all mounted on my AP1200GTO mount(s)

Here is the description page that has images taken using these techiques
on them as well as a paper recently published in "Amateur Astronomy" in
the Fall 2007 issue that I wrote and the original paper I wrote back in
early February of this year when I shot my first round of such images

http://www.narrowbandimaging.com/col...aging_page.htm

I think this is a very new and fresh approach to astroimaging and I know
there are lots of bored imagers out there that simply want to scream if
they see another NGC7000/Pelican in RGB, so here's something new for you
guys to do: brought to you by the same guy that brought you ticolor
emission line imaging about four years ago.

I think the next ground to break may well be out of the visible spectrum
altogether.

Richard

"Richard Crisp" wrote in message
...
Now that narrowband has become mainstream , it is time to start something
completely new again. Back in late January of this year with the helping
hand of a firm push by my friend Liebrecht Venter, I finally did some
experiments I first discussed with him about two years earlier. This was an
experiment to use polarizing filters (analyzers) to dissect various
astronomical targets in an attempt at making a color image in the event
polarized light was found.

snip

interesting stuff, although I find the images a bit difficult to interpret, and less attractive
(aesthetically) to look at than the tricolor emission line images.

I think this is a very new and fresh approach to astroimaging and I know
there are lots of bored imagers out there that simply want to scream if they
see another NGC7000/Pelican in RGB, so here's something new for you guys to
do: brought to you by the same guy that brought you ticolor emission line
imaging about four years ago.

you sure are the king of tricolor in this forum. I always enjoy looking at your results.
--
Martijn (astro-at-pff-software.nl)
10" LX200, Coronado PST, William Optics Z80
EOS350D, ATK 16HRC
www.xs4all.nl/~martlian

In article , Richard Crisp wrote:
Apparently Malin and Pasachoff stopped with the Crab and that is truly a
unique target with a very specific mechanism for creating the polarized
radiation. But there are other mechanisms that can result in polarized light
and one of them are dusty regions aligned in strong magnetic fields with
reflection nebulosity. M78 and its neighbors exhibit such polarization.

Additionally protostellar disks may display polarization such as I found in
Hubble's Variable Nebula, the first such image I have seen of that object
or M78

Another fundamentally different mechanism is observed in the outflows from
M82, which I also imaged using the techiques and is another object for which
I have not seen polarization images.

Another object that I have imaged using the technique is NGC7023 which is
another that I haven't seen any such images published before these I am
linking below.

Might not reflection nebulae provide appreciable polarization too?
Particularly reflection nebulae from supernova remnants such as 1987A, if
you're far enough south.

--
Aidan Karley,
Aberdeen, Scotland
Written at Sat, 04 Aug 2007 23:32 +0100, but posted later.
09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

"Aidan Karley" wrote in message
.. .
In article , Richard Crisp wrote:
Apparently Malin and Pasachoff stopped with the Crab and that is truly a
unique target with a very specific mechanism for creating the polarized
radiation. But there are other mechanisms that can result in polarized
light
and one of them are dusty regions aligned in strong magnetic fields with
reflection nebulosity. M78 and its neighbors exhibit such polarization.

Additionally protostellar disks may display polarization such as I found
in
Hubble's Variable Nebula, the first such image I have seen of that
object
or M78

Another fundamentally different mechanism is observed in the outflows
from
M82, which I also imaged using the techiques and is another object for
which
I have not seen polarization images.

Another object that I have imaged using the technique is NGC7023 which is
another that I haven't seen any such images published before these I am
linking below.

Might not reflection nebulae provide appreciable polarization too?
Particularly reflection nebulae from supernova remnants such as 1987A, if
you're far enough south.


well M78 is a reflection nebula and I got a fair amount in it.