by Guest » Sun Oct 03, 2010 1:14 pm
Ann wrote:Hey, that's a very nice image of M31, Gimmi Ratto! Really very very nice! You bring out the HII regions just beautifully, and the overall color balance seems absolutely great!
When I look at this kind of splendid and perfectly colored portrait of the Andromeda Galaxy, then I'm reminded of how bright the galaxy's large yellow bulge is, how relatively faint the blue arms are, and how small the individual star formation regions are (with the exception of NGC 206, the largest blue patch in the disk). If we had seen M31 from much farther away, say, from a distance of a hundred million light years or so, we might have said that this appeared to be a galaxy devoid of star formation, at least if we had seen it perfectly edge on.
Ann
Ann, thanks a lot, what nice things you said!
Your comment on the brightness of the bulge is so appropriate. Indeed, it takes lots of trickery to keep the bulge at bay while stretching the spiral arms. My standard technique is to create a spline model of the bulge luminosoty that is subtracted from the image before the stetching. Event in that way the bulge comes out.
The contrast of the HII areas is even more drammatic. These areas are really very faint and the photo does not represent at all the true phomoteric relationship between stars, dust and HII nebula.
But it is certainly prettier this way!
Thnks, cheers, gimmi
[quote="Ann"]Hey, that's a very nice image of M31, Gimmi Ratto! Really very very nice! You bring out the HII regions just beautifully, and the overall color balance seems absolutely great!
When I look at this kind of splendid and perfectly colored portrait of the Andromeda Galaxy, then I'm reminded of how bright the galaxy's large yellow bulge is, how relatively faint the blue arms are, and how small the individual star formation regions are (with the exception of NGC 206, the largest blue patch in the disk). If we had seen M31 from much farther away, say, from a distance of a hundred million light years or so, we might have said that this appeared to be a galaxy devoid of star formation, at least if we had seen it perfectly edge on.
Ann[/quote]
Ann, thanks a lot, what nice things you said!
Your comment on the brightness of the bulge is so appropriate. Indeed, it takes lots of trickery to keep the bulge at bay while stretching the spiral arms. My standard technique is to create a spline model of the bulge luminosoty that is subtracted from the image before the stetching. Event in that way the bulge comes out.
The contrast of the HII areas is even more drammatic. These areas are really very faint and the photo does not represent at all the true phomoteric relationship between stars, dust and HII nebula.
But it is certainly prettier this way!
Thnks, cheers, gimmi