ASTRO: Cassiopeia A

I'm quite sure it won't show or show very faintly in your OIII filter.
The IR pass band idea for a very red carbon type star seems the simplest
and most likely solution to me.


Rick

Richard Crisp wrote:

"Rick Johnson" wrote in message
...

My brain finally clicked into gear. Doug suggested it was a carbon star
as it is invisible in blue light, rare for a planetary. Also it is
nearly invisible in my green shot but obvious in the red, far brighter
than your H alpha image. Stefan said his OIII is a visual filter and
thus may not block IR light. After seeing your post by brain finally
clicked. Check the IR DSS image (attached). It's very bright in IR.
Carbon star is looking like the answer.

Since neither of you got much of the remnant in Halpha I wonder if the
red I got was "cool" nitrogen. Possibly sulfur but I lean toward
nitrogen as more likely in a SN blast. It's often the red in planetary
FLIERs

Rick


Stefan and Rick and others:
I asked the Deep Sky Hunters group on Yahoo about this and Matthias
Kronberger replied:

Hi Richard,

this is interesting ... I checked the POSS plates to see in which
colour bands the star is brighter and in which fainter;
interestingly, the stars turned out to be BRIGHTEST in IR, rather
faint on the DSS-I and DSS-II red - and INVISIBLE on all three blue
plates. Especially the blue DSS2 plate should've shown it since its
sensibility on the OIII line is in the range of 90% ! So (at least)
four possibilities remain:

- a new planetary
- a variable star
- the OIII filter has a large bandpass in the near-IR regime
- something even more enigmatic ... ?

are you intending to monitor this star during the next days ? And: do
you know if Stefan took all single-colour images during a single
night ?

----
and then he followed up with this:

Some more notes on the object:

coordinates (USNO B1.0):
23 24 04.87 +58 48 53.8

The object is indeed extremely red; the 2MASS catalogue gives a
colour index J-H = 1.7 ( which is unusually high ); the brightness in
Ks band is 6.8. The star has also a detection in the MSX6C Infrared
Point Source catalogue.

BR

----








Richard Crisp wrote:


by the way I do have a faint star in the same location as your green star
in
your image

could be a planetary....

needs more investigation

"Richard Crisp" wrote in message
.net...


i took a shot at it last night with halpha and after 3.5 hours it was
barely visible.

it appears that the very faint halpha is offset from the o3 in stefan's
image

there may be a blob on the right side of my image but that may be a
problem with the flat field ....


"Stefan Lilge" wrote in message
or-online.net...


Rick's recent very impressive picture of the supernova remnant
Cassiopeia
A
showed me that this object can be imaged by amateurs. For some reason I
always thought it was reserved for the "pros".
I started with the Halpha filter, but the nebula was not visible in the
raw
frames, so I changed to OIII. With the OIII filter the nebula was
clearly
visible. I then added 5 minutes each for RGB to "soup up" the star
colours a
bit.
OIII was taken over two night, unfortunately the second night had only
good
seeing (in the first night it was perfect), so I lost some detail to
gain
a
smoother image.

There is a star to the left from the nebula itself that has the same
teal
colour as the SN remnant in my image because it is only clearly visible
in
the OIII channel. Actually it is quite bright in OIII, while it is just
visible in the Halpha images. None of the RGB exposures captured it.
Maybe
it is not a star but a planetary nebula? On the other hand it looks red
in
Rick's image, which makes it look rather unlikely that it is a PN.

Taken from the middle of Berlin with an 8" SCT at f/6.5, G11 mount,
SXV-H9
camera, 28x10 minutes for OIII, 4x10 minutes for Halpha, 5 minutes each
at
3xbinning for RGB.

The picture can also be found at
http://ccd-astronomy.de/temp/CassAcolourgut.jpg

Stefan

"Rick Johnson" wrote in message
...
I'm quite sure it won't show or show very faintly in your OIII filter. The
IR pass band idea for a very red carbon type star seems the simplest and
most likely solution to me.

I will give it a try in any event




Rick

Richard Crisp wrote:

"Rick Johnson" wrote in message
...

My brain finally clicked into gear. Doug suggested it was a carbon star
as it is invisible in blue light, rare for a planetary. Also it is
nearly invisible in my green shot but obvious in the red, far brighter
than your H alpha image. Stefan said his OIII is a visual filter and
thus may not block IR light. After seeing your post by brain finally
clicked. Check the IR DSS image (attached). It's very bright in IR.
Carbon star is looking like the answer.

Since neither of you got much of the remnant in Halpha I wonder if the
red I got was "cool" nitrogen. Possibly sulfur but I lean toward
nitrogen as more likely in a SN blast. It's often the red in planetary
FLIERs

Rick


Stefan and Rick and others:
I asked the Deep Sky Hunters group on Yahoo about this and Matthias
Kronberger replied:

Hi Richard,

this is interesting ... I checked the POSS plates to see in which
colour bands the star is brighter and in which fainter;
interestingly, the stars turned out to be BRIGHTEST in IR, rather
faint on the DSS-I and DSS-II red - and INVISIBLE on all three blue
plates. Especially the blue DSS2 plate should've shown it since its
sensibility on the OIII line is in the range of 90% ! So (at least)
four possibilities remain:

- a new planetary
- a variable star
- the OIII filter has a large bandpass in the near-IR regime
- something even more enigmatic ... ?

are you intending to monitor this star during the next days ? And: do
you know if Stefan took all single-colour images during a single
night ?

----
and then he followed up with this:

Some more notes on the object:

coordinates (USNO B1.0):
23 24 04.87 +58 48 53.8

The object is indeed extremely red; the 2MASS catalogue gives a
colour index J-H = 1.7 ( which is unusually high ); the brightness in
Ks band is 6.8. The star has also a detection in the MSX6C Infrared
Point Source catalogue.

BR

----








Richard Crisp wrote:


by the way I do have a faint star in the same location as your green
star in
your image

could be a planetary....

needs more investigation

"Richard Crisp" wrote in message
y.net...


i took a shot at it last night with halpha and after 3.5 hours it was
barely visible.

it appears that the very faint halpha is offset from the o3 in stefan's
image

there may be a blob on the right side of my image but that may be a
problem with the flat field ....


"Stefan Lilge" wrote in message
r-online.net...


Rick's recent very impressive picture of the supernova remnant
Cassiopeia
A
showed me that this object can be imaged by amateurs. For some reason
I
always thought it was reserved for the "pros".
I started with the Halpha filter, but the nebula was not visible in
the
raw
frames, so I changed to OIII. With the OIII filter the nebula was
clearly
visible. I then added 5 minutes each for RGB to "soup up" the star
colours a
bit.
OIII was taken over two night, unfortunately the second night had only
good
seeing (in the first night it was perfect), so I lost some detail to
gain
a
smoother image.

There is a star to the left from the nebula itself that has the same
teal
colour as the SN remnant in my image because it is only clearly
visible
in
the OIII channel. Actually it is quite bright in OIII, while it is
just
visible in the Halpha images. None of the RGB exposures captured it.
Maybe
it is not a star but a planetary nebula? On the other hand it looks
red
in
Rick's image, which makes it look rather unlikely that it is a PN.

Taken from the middle of Berlin with an 8" SCT at f/6.5, G11 mount,
SXV-H9
camera, 28x10 minutes for OIII, 4x10 minutes for Halpha, 5 minutes
each
at
3xbinning for RGB.

The picture can also be found at
http://ccd-astronomy.de/temp/CassAcolourgut.jpg

Stefan

Richard and Rick,

thanks for clearing this up. If it clears up next weekend I may still be
tempted to do an IR-pass image just for fun.

Stefan

"Richard Crisp" schrieb im Newsbeitrag
...

"Rick Johnson" wrote in message
...
My brain finally clicked into gear. Doug suggested it was a carbon star
as it is invisible in blue light, rare for a planetary. Also it is
nearly invisible in my green shot but obvious in the red, far brighter
than your H alpha image. Stefan said his OIII is a visual filter and
thus may not block IR light. After seeing your post by brain finally
clicked. Check the IR DSS image (attached). It's very bright in IR.
Carbon star is looking like the answer.

Since neither of you got much of the remnant in Halpha I wonder if the
red I got was "cool" nitrogen. Possibly sulfur but I lean toward
nitrogen as more likely in a SN blast. It's often the red in planetary
FLIERs

Rick

Stefan and Rick and others:
I asked the Deep Sky Hunters group on Yahoo about this and Matthias
Kronberger replied:

Hi Richard,

this is interesting ... I checked the POSS plates to see in which
colour bands the star is brighter and in which fainter;
interestingly, the stars turned out to be BRIGHTEST in IR, rather
faint on the DSS-I and DSS-II red - and INVISIBLE on all three blue
plates. Especially the blue DSS2 plate should've shown it since its
sensibility on the OIII line is in the range of 90% ! So (at least)
four possibilities remain:

- a new planetary
- a variable star
- the OIII filter has a large bandpass in the near-IR regime
- something even more enigmatic ... ?

are you intending to monitor this star during the next days ? And: do
you know if Stefan took all single-colour images during a single
night ?

----
and then he followed up with this:

Some more notes on the object:

coordinates (USNO B1.0):
23 24 04.87 +58 48 53.8

The object is indeed extremely red; the 2MASS catalogue gives a
colour index J-H = 1.7 ( which is unusually high ); the brightness in
Ks band is 6.8. The star has also a detection in the MSX6C Infrared
Point Source catalogue.

BR

----








Richard Crisp wrote:

by the way I do have a faint star in the same location as your green
star in
your image

could be a planetary....

needs more investigation

"Richard Crisp" wrote in message
t...

i took a shot at it last night with halpha and after 3.5 hours it was
barely visible.

it appears that the very faint halpha is offset from the o3 in stefan's
image

there may be a blob on the right side of my image but that may be a
problem with the flat field ....


"Stefan Lilge" wrote in message
or-online.net...

Rick's recent very impressive picture of the supernova remnant
Cassiopeia
A
showed me that this object can be imaged by amateurs. For some reason I
always thought it was reserved for the "pros".
I started with the Halpha filter, but the nebula was not visible in the
raw
frames, so I changed to OIII. With the OIII filter the nebula was
clearly
visible. I then added 5 minutes each for RGB to "soup up" the star
colours a
bit.
OIII was taken over two night, unfortunately the second night had only
good
seeing (in the first night it was perfect), so I lost some detail to
gain
a
smoother image.

There is a star to the left from the nebula itself that has the same
teal
colour as the SN remnant in my image because it is only clearly visible
in
the OIII channel. Actually it is quite bright in OIII, while it is just
visible in the Halpha images. None of the RGB exposures captured it.
Maybe
it is not a star but a planetary nebula? On the other hand it looks red
in
Rick's image, which makes it look rather unlikely that it is a PN.

Taken from the middle of Berlin with an 8" SCT at f/6.5, G11 mount,
SXV-H9
camera, 28x10 minutes for OIII, 4x10 minutes for Halpha, 5 minutes each
at
3xbinning for RGB.

The picture can also be found at
http://ccd-astronomy.de/temp/CassAcolourgut.jpg

Stefan

i was thinking using my UV short pass too...

and an NIR long pass


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

thanks for clearing this up. If it clears up next weekend I may still be
tempted to do an IR-pass image just for fun.

Stefan

"Richard Crisp" schrieb im Newsbeitrag
...

"Rick Johnson" wrote in message
...
My brain finally clicked into gear. Doug suggested it was a carbon star
as it is invisible in blue light, rare for a planetary. Also it is
nearly invisible in my green shot but obvious in the red, far brighter
than your H alpha image. Stefan said his OIII is a visual filter and
thus may not block IR light. After seeing your post by brain finally
clicked. Check the IR DSS image (attached). It's very bright in IR.
Carbon star is looking like the answer.

Since neither of you got much of the remnant in Halpha I wonder if the
red I got was "cool" nitrogen. Possibly sulfur but I lean toward
nitrogen as more likely in a SN blast. It's often the red in planetary
FLIERs

Rick

Stefan and Rick and others:
I asked the Deep Sky Hunters group on Yahoo about this and Matthias
Kronberger replied:

Hi Richard,

this is interesting ... I checked the POSS plates to see in which
colour bands the star is brighter and in which fainter;
interestingly, the stars turned out to be BRIGHTEST in IR, rather
faint on the DSS-I and DSS-II red - and INVISIBLE on all three blue
plates. Especially the blue DSS2 plate should've shown it since its
sensibility on the OIII line is in the range of 90% ! So (at least)
four possibilities remain:

- a new planetary
- a variable star
- the OIII filter has a large bandpass in the near-IR regime
- something even more enigmatic ... ?

are you intending to monitor this star during the next days ? And: do
you know if Stefan took all single-colour images during a single
night ?

----
and then he followed up with this:

Some more notes on the object:

coordinates (USNO B1.0):
23 24 04.87 +58 48 53.8

The object is indeed extremely red; the 2MASS catalogue gives a
colour index J-H = 1.7 ( which is unusually high ); the brightness in
Ks band is 6.8. The star has also a detection in the MSX6C Infrared
Point Source catalogue.

BR

----








Richard Crisp wrote:

by the way I do have a faint star in the same location as your green
star in
your image

could be a planetary....

needs more investigation

"Richard Crisp" wrote in message
t...

i took a shot at it last night with halpha and after 3.5 hours it was
barely visible.

it appears that the very faint halpha is offset from the o3 in stefan's
image

there may be a blob on the right side of my image but that may be a
problem with the flat field ....


"Stefan Lilge" wrote in message
r-online.net...

Rick's recent very impressive picture of the supernova remnant
Cassiopeia
A
showed me that this object can be imaged by amateurs. For some reason
I
always thought it was reserved for the "pros".
I started with the Halpha filter, but the nebula was not visible in
the
raw
frames, so I changed to OIII. With the OIII filter the nebula was
clearly
visible. I then added 5 minutes each for RGB to "soup up" the star
colours a
bit.
OIII was taken over two night, unfortunately the second night had only
good
seeing (in the first night it was perfect), so I lost some detail to
gain
a
smoother image.

There is a star to the left from the nebula itself that has the same
teal
colour as the SN remnant in my image because it is only clearly
visible
in
the OIII channel. Actually it is quite bright in OIII, while it is
just
visible in the Halpha images. None of the RGB exposures captured it.
Maybe
it is not a star but a planetary nebula? On the other hand it looks
red
in
Rick's image, which makes it look rather unlikely that it is a PN.

Taken from the middle of Berlin with an 8" SCT at f/6.5, G11 mount,
SXV-H9
camera, 28x10 minutes for OIII, 4x10 minutes for Halpha, 5 minutes
each
at
3xbinning for RGB.

The picture can also be found at
http://ccd-astronomy.de/temp/CassAcolourgut.jpg

Stefan