NGC 2070: The Tarantula Nebula
Credit: George Ionas, data; Emanuele Colognato, post-processing http://dl.dropbox.com/u/1427295/NGC2070_Full.jpg [attachment=5]NGC2070_small.jpg[/attachment][/i]
NGC 2170 in Monoceros
Copyright: Louie Atalasidis [attachment=4]NGC-2170.jpg[/attachment][/i]
Hmm, that's a very nice image of the Pleiades, Ferran Bosch. Very blue, too. But considering it's so popular to chase down every last photon of red hydrogen alpha emission and paint skyscapes all red, why not chase down the blue reflection nebulosity photons with a similar diligence?
I have to share my experience and a result from doing astrophotography at 4100 meters above sea level. Once, I dreamed of doing something else than just pretty picture (wanted to try something more scientifical). This image is EVERYTHING BUT PRETTY picture. The interesting thing is the band spectra of light from 820nm (used Astrodon's Sloan z' filter) to some 1um where the spectral response of CCD sensor Sony ICX285AL reaches zero. I used dithering to get rid of cosmics rays. I had big trouble doing flats. The image is noisy, but what can one expect from amateur equipment in NIR photography. The top image is monochrome only, as it's NIR luminance only. The bottom image is a pseudo-false colored monochromatic data.
Ann wrote:Hmm, that's a very nice image of the Pleiades, Ferran Bosch. Very blue, too. But considering it's so popular to chase down every last photon of red hydrogen alpha emission and paint skyscapes all red, why not chase down the blue reflection nebulosity photons with a similar diligence?
Ann
¿Too blue? is a reflection nebula, young stars, and no trace of Ha... ¿still too blue?
Re: Recent Submissions: 2010 November 19-22
Posted: Fri Nov 19, 2010 4:12 pm
by Ann
caliu wrote:
Ann wrote:Hmm, that's a very nice image of the Pleiades, Ferran Bosch. Very blue, too. But considering it's so popular to chase down every last photon of red hydrogen alpha emission and paint skyscapes all red, why not chase down the blue reflection nebulosity photons with a similar diligence?
Ann
¿Too blue? is a reflection nebula, young stars, and no trace of Ha... ¿still too blue?
I meant that there is scattered blue light over almost the entire field, and images of the Pleiades and their surroundings don't usually look like that.
But I didn't say that the picture was too blue, rather that astroimager Ferran Bosch had done a good job chasing down the blue photons here. I meant that as praise!
Thanks for the galaxies, Adam! NGC 7814 looks really good. It is fun to see how tendrils of dust rise from the otherwise perfectly straight main dust lane. Also, it is fun to see how the stars in the disk on the right appear to take on a slightly "bluer" color - of course their color is not blue, but perhaps whitish. In this galaxy made up of old star, the stars on the right in the disk may possibly be merely middle-aged.
Of course I like your picture of NGC 925 even better. The blue color of the disk, the many clusters and condensations and all the pink emission nebulae: all appeal to me very much. Recently I had 925 posts, and I realized that the number 925 rang a bell. I googled "NGC 925" and got pictures that were good enough to show me that NGC 925 was indeed a nice starforming galaxy, but the pictures were badly resolved and had bad color balancies. Your picture is the one I would have wanted to find when I was trying to make myself "NGC 925" for a day!
Ann
Re: Recent Submissions: 2010 November 19-22
Posted: Sat Nov 20, 2010 5:41 am
by Ann
Alfonso Carreño, your picture of IC 405 and IC 410 is interesting. The picture is really well resolved. The color is interesting and probably not what most people would expect. But when I look at the little asterism of stars "swimming" between these two nebula, an asterism called "The Leaping Minnow", I find that the colors here are subtle, but true. The topmost star is the yellowest - check, because it is a K giant. The star on the middle right is the bluest - check, because it is a favorite star of mine, IQ Aurigae, which is remarkably blue for its spectral class. The other stars take on intermediate hues, which is perfectly correct, too. So based on how you portray the star colors here, I'd say that you are doing the nebulae justice, too. This is probably what nebulae look like if you are photographing without making an effort to coax the red color out of them.
Interesting! Thank you for this "new view" of emission nebulae!
This month the Moon will be full on the 21st and, according to an old definition, it will also be “Blue“ being the third of four full moons in the same season. Considering that weather is forecasted bad for the next few days, I anticipated the shot on November 19 when our natural satellite was not Full, not Blue but looked great anyway as rising alongside the Superga church while another wonder from the sky was joining the scene.
Re: Recent Submissions: 2010 November 19-22
Posted: Sat Nov 20, 2010 9:04 am
by bystander
StefanoDeRosa wrote:Waiting for the Blue Moon http://ofpink.wordpress.com/
Copyright: Stefano De Rosa http://ofpink.files.wordpress.com/2010/ ... uperga.jpg
This month the Moon will be full on the 21st and, according to an old definition, it will also be “Blue“ being the third of four full moons in the same season. Considering that weather is forecasted bad for the next few days, I anticipated the shot on November 19 when our natural satellite was not Full, not Blue but looked great anyway as rising alongside the Superga church while another wonder from the sky was joining the scene.
Ann wrote:Alfonso Carreño, your picture of IC 405 and IC 410 is interesting. The picture is really well resolved. The color is interesting and probably not what most people would expect. But when I look at the little asterism of stars "swimming" between these two nebula, an asterism called "The Leaping Minnow", I find that the colors here are subtle, but true. The topmost star is the yellowest - check, because it is a K giant. The star on the middle right is the bluest - check, because it is a favorite star of mine, IQ Aurigae, which is remarkably blue for its spectral class. The other stars take on intermediate hues, which is perfectly correct, too. So based on how you portray the star colors here, I'd say that you are doing the nebulae justice, too. This is probably what nebulae look like if you are photographing without making an effort to coax the red color out of them.
Interesting! Thank you for this "new view" of emission nebulae!
Ann
Ann, thanks for your visit and comment, you are right when they comment that my intention is to have a "new view" of these nebulae.
Sorry if my English is not correct.
A greeting from Alfonso Carreño .-)
Re: Recent Submissions: 2010 November 19-22
Posted: Sat Nov 20, 2010 2:58 pm
by owlice
Winter Milky Way
Copyright: Tunç Tezel [attachment=0]RasLanufHartley2Leonid.jpg[/attachment][/i]
Stefano de Rosa, that is a truly magical picture. The Moon looks as insubstantial and lightweight as a balloon as it floats behind that magnificent building.
And I really like that seeming encounter between two striped and apparently similarly sized objects in space, the ISS and Jupiter!
Robert Gendler, that is a very handsome image of beautiful spiral galaxy NGC 1672. I know that the galaxy looks even better on your own homepage, where we can see the galaxy at a larger size. As for the closeup of the nucleus, I guess those blue and bluish knots are large clusters, aren't they?
Rogelio Bernal Andreo, you know that I am one of your diehard fans! Your image of the region around Polaris is very very beuatiful and delightfully detailed. It is certainly fascinating to see all that galactic cirrus. However, as a color commentator, I've got to say something... Polaris isn't blue! It has a color index of +0.636, which makes it marginally yellower than the Sun. Okay, but when I look at that picture again, it looks a little bit as if that blue light surrounding Polaris might be a reflection nebula, in which case the blue color would certainly be all right. And there sure is a lot of cirrus around Polaris, but is the cirrus at the same distance from us as Polaris? I have never heard that Polaris would be immersed in a reflection nebula, and my software says that the famous star is unreddened. So I doubt that the color is really right here, but the picture is definitely delightful!
Ann
Re: Recent Submissions: 2010 November 19-22
Posted: Sun Nov 21, 2010 8:24 am
by RBAF
Hi Ann,
I know Polaris isn't blue but the whole image was color-balanced without any kind of masks (meaning there has been no selective color adjustments anywhere in the image), and the spectra type and B-V of other stars seem correct, always understanding that saturation will always be dialed up or down to the preferences of the person processing the image (saturation, not color balance). I do not know the explanation as of why all that blue around a F7 type star, but that's how it came out, it's not an artistic license of any kind. I would love to hear an explanation that would make sense, but so far, all the comments I've got simply point out the obvious, that the star isn't blue Well, whatever the cause, there is a lot of blue the way it came out of my scope
Thanks!
Rogelio
Re: Recent Submissions: 2010 November 19-22
Posted: Sun Nov 21, 2010 9:32 am
by StefanoDeRosa
bystander and Ann, many thanks for your kind comments
but the whole image was color-balanced without any kind of masks (meaning there has been no selective color adjustments anywhere in the image), and the spectra type and B-V of other stars seem correct, always understanding that saturation will always be dialed up or down to the preferences of the person processing the image (saturation, not color balance). I do not know the explanation as of why all that blue around a F7 type star, but that's how it came out, it's not an artistic license of any kind. I would love to hear an explanation that would make sense, but so far, all the comments I've got simply point out the obvious, that the star isn't blue 
