by Ann » Mon Sep 20, 2010 5:35 pm
LLacertae wrote:Hi everyone!
I am happy that my picture of n6384 caused confusion
criticism is very important for me! Thank you Ann!
And you are right Ann, it is Hubble material and therefore has an total resolution of >3000px.
I love to experiment with the perception of color and contrast in astronomical pictures, so your arguments are comprehensible
I hope you like this dusty beauty better:
"The little Sombrero" NGC 7814
http://hubble-unseen.at.tf/
Copyright: Nikolaus Sulzenauer HST/NASA/ESA
Zoomable version
You're welcome, LLacertae! I didn't mean to criticize your image. Hey, I think your color balance is slightly blue, but the Hubble people themselves are usually a lot worse! As for NGC 6384, I actually believe that the color of this galaxy
is weird. So I'm not criticizing your image, rather pointing out the strangeness of NGC 6384 itself.
As for NGC 7814, I think that the bulge of that galaxy is also too blue in your image. But then, I don't trust the Hubble people to bring out the yellow color that I expect from bulges.
I tried to assess the "true" color of NGC 7814 by googling several pictures of it. It is clear from the pictures that NGC 7814 is indeed a "little Sombrero", a cousin of M 104. Like the more famous Messier galaxy, NGC 7814 has a very large bulge and a thin and distinct dust lane which probably contains no star formation. The color index of NGC 7814 is +1.00 (B-V), which is even redder than the Sombrero's (+0.97). Their U-B indexes are very similar too, although here NGC 7814 is marginally bluer (+0.50 versus +0.52 for the Sombrero).
A picture of NGC 7814 that I would like to post here for comparison is this one:
I'd say that the colors here are definitely enhanced. The image does bring out how the halo is bluer, or at least less red, farther away from the nucleus. This effect may be quite subtle, however, and I'm not at all sure that the Hubble picture would bring it out. It is also clear that the reddest part of the galaxy is the dust lane, which is not surprising, certainly in view of the lack of star formation there.
I also recommend a Hubble image that resolves NGC 7814 into stars. The picture is so big that I'm just posting it as a link:
http://quarks.maynau.com/ngc7814-poor.jpg
I think it is possible to discern what might just possibly be a very, very small number of blue stars in the disk of NGC 7814. Overall, the galaxy is completely dominated by "beige" - that is, pale yellow - stars.
But I enjoy your image too, LLacertae! Do post your own versions of more Hubble images!
Ann
[quote="LLacertae"]Hi everyone!
I am happy that my picture of n6384 caused confusion :) criticism is very important for me! Thank you Ann!
And you are right Ann, it is Hubble material and therefore has an total resolution of >3000px.
I love to experiment with the perception of color and contrast in astronomical pictures, so your arguments are comprehensible :P
I hope you like this dusty beauty better:
[size=120][b]"The little Sombrero" NGC 7814[/b][/size]
[url]http://hubble-unseen.at.tf/[/url]
Copyright: Nikolaus Sulzenauer HST/NASA/ESA
[img2]http://409557.com/ngc7814-public-2000.jpg[/img2]
[url=http://quarks.maynau.com/nova/ext/n7814-viewmode.shtml]Zoomable version[/url][/quote]
You're welcome, LLacertae! I didn't mean to criticize your image. Hey, I think your color balance is slightly blue, but the Hubble people themselves are usually a lot worse! As for NGC 6384, I actually believe that the color of this galaxy [i]is[/i] weird. So I'm not criticizing your image, rather pointing out the strangeness of NGC 6384 itself.
As for NGC 7814, I think that the bulge of that galaxy is also too blue in your image. But then, I don't trust the Hubble people to bring out the yellow color that I expect from bulges.
I tried to assess the "true" color of NGC 7814 by googling several pictures of it. It is clear from the pictures that NGC 7814 is indeed a "little Sombrero", a cousin of M 104. Like the more famous Messier galaxy, NGC 7814 has a very large bulge and a thin and distinct dust lane which probably contains no star formation. The color index of NGC 7814 is +1.00 (B-V), which is even redder than the Sombrero's (+0.97). Their U-B indexes are very similar too, although here NGC 7814 is marginally bluer (+0.50 versus +0.52 for the Sombrero).
A picture of NGC 7814 that I would like to post here for comparison is this one:
[img2]http://www.astroimages.com/NGC7814.jpg[/img2]
I'd say that the colors here are definitely enhanced. The image does bring out how the halo is bluer, or at least less red, farther away from the nucleus. This effect may be quite subtle, however, and I'm not at all sure that the Hubble picture would bring it out. It is also clear that the reddest part of the galaxy is the dust lane, which is not surprising, certainly in view of the lack of star formation there.
I also recommend a Hubble image that resolves NGC 7814 into stars. The picture is so big that I'm just posting it as a link:
[url]http://quarks.maynau.com/ngc7814-poor.jpg[/url]
I think it is possible to discern what might just possibly be a very, very small number of blue stars in the disk of NGC 7814. Overall, the galaxy is completely dominated by "beige" - that is, pale yellow - stars.
But I enjoy your image too, LLacertae! Do post your own versions of more Hubble images!
Ann