ASTRO: IC 342 The Hidden Galaxy

IC 342 The Hidden Galaxy. Heavily obscured behind the dust of our
galaxy it is difficult to observe. Without the dust it would be one of
the showpieces of the sky. It's distance has been hard to pin down with
estimates of 9 to 13 million light years most commonly seen. In March
of this year a team using Hubble images claim it is 3.93 megaparsecs
distant give or take 0.1 megaparsec. For the megaparsec challenged out
there that translates to 12.8 million light years give or take 0.3
million light years. http://arxiv.org/abs/1003.0321. The article is an
interesting read and not as deep as many.

I don't like my color data. Being so heavily obscured it is very red as
the blue and some of the green light it emits is absorbed by the dust in
our galaxy turning it red same as dust in our atmosphere turns the sun
red at sunset. Complicating this task is the extinction due to dust
varies across the galaxy. It's angular size is great enough that parts
are obscured by different dust clouds of different densities. I tried
to compensate for the dust but the usual formulas didn't work well. I
thought it a good night but apparently it wasn't as good as I thought.
I will try again with my new filters when I get a chance but for now
this will have to do. HII data would be nice to add as well as this one
is full of HII regions that I lost trying to compensate for extinction.

It is classed as SAB(rs)cd;Sy2 with an HII core. You have to look hard
to find the short bar. It and Maffei 1 anchor a group of galaxies just
beyond our local group. Most are heavily obscured by dust, many,
including Maffei 1 are virtually invisible in ordinary light and only
seen to their true extent by infrared telescopes. 5 years ago I tried
to image it and Maffei II but my technique was poor resulting in very
little being seen and then with no color data. I need to try again.

There are only 3 other galaxies listed in NED in the image. Two are
starlike until you blow up the image. The third is a very blue object
at about pixel 179x821 on the far left side of the image 179 pixels in.
To me it looks like part of IC 342 as there's a lot of faint glow of
the galaxy shining through the gunk of our galaxy around it. I took it
to be another blue HII region but NED say it is IRAS 03443+6754 an IR
source and LEDA 166480 a galaxy. Thus it is a high IR emitting galaxy.
But there's an "essential note" at NED saying "Claimed to be part of
IC 0342 by Lawrence, et al.(1999MNRAS.308..897L)." I'm with Lawrence.

On the east side of the galaxy below a string of blue starlike HII
regions is a very red oval (mostly horizontal). Sure looks like an
elliptical galaxy that's severely reddened from its natural red color.
But NED shows only an HII region at this position. After a lot of
processing various ways I have decided NED is right. It appears to
really be two red stars not quite resolved and a red HII emission
feature. While Hubble imaged parts of the galaxy it missed this area by
about 1.5 minutes of arc. Close but no image to settle this. For now
I'll agree with NED.

This marks the last of my December images, with only three due to severe
cloud cover there weren't many. Fortunately January was a better month
with 18 objects imaged over 5 imaging days, 12 being Arp galaxies. Not
good but sure beats December with one imaging night that was cloud
shortened.

14" LX200R @ f/10, L=8x10' RGB=4x10'x3, STL-11000XM, Paramount ME

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".

Rick,

amazing how much contrast and detail you got in this faint spiral. Most
images I have seen (including my own) show this as a faint "ghost" of a
galaxy because of the dust that hides it.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
ter.com...
IC 342 The Hidden Galaxy. Heavily obscured behind the dust of our
galaxy it is difficult to observe. Without the dust it would be one of
the showpieces of the sky. It's distance has been hard to pin down with
estimates of 9 to 13 million light years most commonly seen. In March
of this year a team using Hubble images claim it is 3.93 megaparsecs
distant give or take 0.1 megaparsec. For the megaparsec challenged out
there that translates to 12.8 million light years give or take 0.3
million light years. http://arxiv.org/abs/1003.0321. The article is an
interesting read and not as deep as many.

I don't like my color data. Being so heavily obscured it is very red as
the blue and some of the green light it emits is absorbed by the dust in
our galaxy turning it red same as dust in our atmosphere turns the sun
red at sunset. Complicating this task is the extinction due to dust
varies across the galaxy. It's angular size is great enough that parts
are obscured by different dust clouds of different densities. I tried
to compensate for the dust but the usual formulas didn't work well. I
thought it a good night but apparently it wasn't as good as I thought.
I will try again with my new filters when I get a chance but for now
this will have to do. HII data would be nice to add as well as this one
is full of HII regions that I lost trying to compensate for extinction.

It is classed as SAB(rs)cd;Sy2 with an HII core. You have to look hard
to find the short bar. It and Maffei 1 anchor a group of galaxies just
beyond our local group. Most are heavily obscured by dust, many,
including Maffei 1 are virtually invisible in ordinary light and only
seen to their true extent by infrared telescopes. 5 years ago I tried
to image it and Maffei II but my technique was poor resulting in very
little being seen and then with no color data. I need to try again.

There are only 3 other galaxies listed in NED in the image. Two are
starlike until you blow up the image. The third is a very blue object
at about pixel 179x821 on the far left side of the image 179 pixels in.
To me it looks like part of IC 342 as there's a lot of faint glow of
the galaxy shining through the gunk of our galaxy around it. I took it
to be another blue HII region but NED say it is IRAS 03443+6754 an IR
source and LEDA 166480 a galaxy. Thus it is a high IR emitting galaxy.
But there's an "essential note" at NED saying "Claimed to be part of
IC 0342 by Lawrence, et al.(1999MNRAS.308..897L)." I'm with Lawrence.

On the east side of the galaxy below a string of blue starlike HII
regions is a very red oval (mostly horizontal). Sure looks like an
elliptical galaxy that's severely reddened from its natural red color.
But NED shows only an HII region at this position. After a lot of
processing various ways I have decided NED is right. It appears to
really be two red stars not quite resolved and a red HII emission
feature. While Hubble imaged parts of the galaxy it missed this area by
about 1.5 minutes of arc. Close but no image to settle this. For now
I'll agree with NED.

This marks the last of my December images, with only three due to severe
cloud cover there weren't many. Fortunately January was a better month
with 18 objects imaged over 5 imaging days, 12 being Arp galaxies. Not
good but sure beats December with one imaging night that was cloud
shortened.

14" LX200R @ f/10, L=8x10' RGB=4x10'x3, STL-11000XM, Paramount ME

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".

I sort of hid its "hidden" nature by my processing.

I'm finding haze like this can be cut significantly by the high pass
filter. I select out the stars leaving only the galaxy. Then I mask
out small high contrast detail in the galaxy with a fuzzy mask so they
get some of the high pass filter but not a lot. Takes so experimenting
until you learn how much to hide these. Then I make several copies of
the result and run a high pass at about 1.5 radius, 2.5, 3.5, etc.
through 7.5. Amazing what you can do when combining these (Overlay
mode, sometime Softlight). Might not use them all and some will get
near 100% while others far less. Takes a bit of playing around to find
the right combination. Goes fairly fast once you are used to it. Low
radius brings out fine detail and ignores large features while large
radius brings out the larger features. Once done just add back the
stars of course.

Rick

On 10/17/2010 5:18 PM, Stefan Lilge wrote:
Rick,

amazing how much contrast and detail you got in this faint spiral. Most
images I have seen (including my own) show this as a faint "ghost" of a
galaxy because of the dust that hides it.

Stefan

"Rick schrieb im Newsbeitrag
ter.com...
IC 342 The Hidden Galaxy. Heavily obscured behind the dust of our
galaxy it is difficult to observe. Without the dust it would be one of
the showpieces of the sky. It's distance has been hard to pin down with
estimates of 9 to 13 million light years most commonly seen. In March
of this year a team using Hubble images claim it is 3.93 megaparsecs
distant give or take 0.1 megaparsec. For the megaparsec challenged out
there that translates to 12.8 million light years give or take 0.3
million light years. http://arxiv.org/abs/1003.0321. The article is an
interesting read and not as deep as many.

I don't like my color data. Being so heavily obscured it is very red as
the blue and some of the green light it emits is absorbed by the dust in
our galaxy turning it red same as dust in our atmosphere turns the sun
red at sunset. Complicating this task is the extinction due to dust
varies across the galaxy. It's angular size is great enough that parts
are obscured by different dust clouds of different densities. I tried
to compensate for the dust but the usual formulas didn't work well. I
thought it a good night but apparently it wasn't as good as I thought.
I will try again with my new filters when I get a chance but for now
this will have to do. HII data would be nice to add as well as this one
is full of HII regions that I lost trying to compensate for extinction.

It is classed as SAB(rs)cd;Sy2 with an HII core. You have to look hard
to find the short bar. It and Maffei 1 anchor a group of galaxies just
beyond our local group. Most are heavily obscured by dust, many,
including Maffei 1 are virtually invisible in ordinary light and only
seen to their true extent by infrared telescopes. 5 years ago I tried
to image it and Maffei II but my technique was poor resulting in very
little being seen and then with no color data. I need to try again.

There are only 3 other galaxies listed in NED in the image. Two are
starlike until you blow up the image. The third is a very blue object
at about pixel 179x821 on the far left side of the image 179 pixels in.
To me it looks like part of IC 342 as there's a lot of faint glow of
the galaxy shining through the gunk of our galaxy around it. I took it
to be another blue HII region but NED say it is IRAS 03443+6754 an IR
source and LEDA 166480 a galaxy. Thus it is a high IR emitting galaxy.
But there's an "essential note" at NED saying "Claimed to be part of
IC 0342 by Lawrence, et al.(1999MNRAS.308..897L)." I'm with Lawrence.

On the east side of the galaxy below a string of blue starlike HII
regions is a very red oval (mostly horizontal). Sure looks like an
elliptical galaxy that's severely reddened from its natural red color.
But NED shows only an HII region at this position. After a lot of
processing various ways I have decided NED is right. It appears to
really be two red stars not quite resolved and a red HII emission
feature. While Hubble imaged parts of the galaxy it missed this area by
about 1.5 minutes of arc. Close but no image to settle this. For now
I'll agree with NED.

This marks the last of my December images, with only three due to severe
cloud cover there weren't many. Fortunately January was a better month
with 18 objects imaged over 5 imaging days, 12 being Arp galaxies. Not
good but sure beats December with one imaging night that was cloud
shortened.

14" LX200R @ f/10, L=8x10' RGB=4x10'x3, STL-11000XM, Paramount ME

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".





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

core detail is outstanding.

On Sun, 17 Oct 2010 00:10:42 -0500, Rick Johnson
wrote:

IC 342 The Hidden Galaxy. Heavily obscured behind the dust of our
galaxy it is difficult to observe. Without the dust it would be one of
the showpieces of the sky. It's distance has been hard to pin down with
estimates of 9 to 13 million light years most commonly seen. In March
of this year a team using Hubble images claim it is 3.93 megaparsecs
distant give or take 0.1 megaparsec. For the megaparsec challenged out
there that translates to 12.8 million light years give or take 0.3
million light years. http://arxiv.org/abs/1003.0321. The article is an
interesting read and not as deep as many.

I don't like my color data. Being so heavily obscured it is very red as
the blue and some of the green light it emits is absorbed by the dust in
our galaxy turning it red same as dust in our atmosphere turns the sun
red at sunset. Complicating this task is the extinction due to dust
varies across the galaxy. It's angular size is great enough that parts
are obscured by different dust clouds of different densities. I tried
to compensate for the dust but the usual formulas didn't work well. I
thought it a good night but apparently it wasn't as good as I thought.
I will try again with my new filters when I get a chance but for now
this will have to do. HII data would be nice to add as well as this one
is full of HII regions that I lost trying to compensate for extinction.

It is classed as SAB(rs)cd;Sy2 with an HII core. You have to look hard
to find the short bar. It and Maffei 1 anchor a group of galaxies just
beyond our local group. Most are heavily obscured by dust, many,
including Maffei 1 are virtually invisible in ordinary light and only
seen to their true extent by infrared telescopes. 5 years ago I tried
to image it and Maffei II but my technique was poor resulting in very
little being seen and then with no color data. I need to try again.

There are only 3 other galaxies listed in NED in the image. Two are
starlike until you blow up the image. The third is a very blue object
at about pixel 179x821 on the far left side of the image 179 pixels in.
To me it looks like part of IC 342 as there's a lot of faint glow of
the galaxy shining through the gunk of our galaxy around it. I took it
to be another blue HII region but NED say it is IRAS 03443+6754 an IR
source and LEDA 166480 a galaxy. Thus it is a high IR emitting galaxy.
But there's an "essential note" at NED saying "Claimed to be part of
IC 0342 by Lawrence, et al.(1999MNRAS.308..897L)." I'm with Lawrence.

On the east side of the galaxy below a string of blue starlike HII
regions is a very red oval (mostly horizontal). Sure looks like an
elliptical galaxy that's severely reddened from its natural red color.
But NED shows only an HII region at this position. After a lot of
processing various ways I have decided NED is right. It appears to
really be two red stars not quite resolved and a red HII emission
feature. While Hubble imaged parts of the galaxy it missed this area by
about 1.5 minutes of arc. Close but no image to settle this. For now
I'll agree with NED.

This marks the last of my December images, with only three due to severe
cloud cover there weren't many. Fortunately January was a better month
with 18 objects imaged over 5 imaging days, 12 being Arp galaxies. Not
good but sure beats December with one imaging night that was cloud
shortened.

14" LX200R @ f/10, L=8x10' RGB=4x10'x3, STL-11000XM, Paramount ME

Rick