M-33 comparison image

This image partially illustrates how important additional "subs" (light exposures) are in helping to define an image. The M-33 on the left integrates the image on the right (15x3min exposures, collected on September 13) with an additional 60 minutes of subs (20x3min, collected on October 11, 2007).
The differences are subtle but nonetheless discernible. I note four:
First, the extent or sweep of the spiral arms has been clarified. The diffuse nature of M-33 leads to a very low surface brightness.
Second, there is more "texture" or overall detail to the image. The 45 minute exposure required smoothing via a Gaussian blur. The 105 minute combined stack has been smoothed, but only by a small amount.
Third, the hydrogen alpha regions (with the reddish tinge) stand out more clearly, not only in the named regions, but also as H-alpha is intermixed with the arms.
And finally, the overall coloration of the image is, to my eye, more pleasing, moving from a muddier-greenish tinge in the smaller stack to a "ruddier" and somewhat bluer coloration in the larger stack.

Acquisition and Processing
Acquisition and processing per usual. Stacks combined with IP. Composite image created with PS CS2.

IC-405, The Flaming Star Nebula

Astrophysical data on the Flaming Star Nebula is easy to find online. Click here for the NASA overview. After a couple of quick and dirty processing attempts that yielded a drab image, it suddently occurred to me that the goal for my processing should be "flame-like."

The star AE Auriga is powering the "flame," so to speak. There's an interesting astrophysical history here, since "AE Aurigae's story is inextricably linked to another star called Mu Columbae. Around 2.7 million years ago these two stars were formed and had a close encounter with one another in the Great Orion Nebula. The encounter was so close (another star was certainly involved) that each of them was ejected from the Orion complex never to return again. Currently these stars are 66 degrees away from one another in the sky. Astronomer's discovered these two runaway stars by measuring their apparent (fast) motion and noting that if you work backwards in time - the origin is in the same place at the same time! But AE Auriga is certainly the more glamorous of the two stars since it just happens to be moving through a region of gas that makes it look like a 'Flaming Star.' " Source

Acquisition and Processing
SV115 at f/5.6 on the CGE, SBIG ST2000XCM, 22 subs at 3 minutes, acquired using CCDSOFT v.5, processed in ImagesPlus 3, beta9 and PhotoShop CS2.

M-31 - The Andromeda Galaxy

There's no need to go on about M-31 -- clearly one of the most beautiful and photographed DSOs. Rob Gendler's M-31 just about takes your breathe away (click here). Note how Gendler captures multiple colors. He emphasizes that his processing, which is truly spectacular, is done to suit his aesthetic taste. I've processed more than one version from these subs, but this one is my favorite. Why? Because the "rifts" or dust lanes are so plainly obvious. As Eric Jacob notes, someone ought to sweep this "dirty" galaxy up.

In any case, here are a few quick points about the Great Galaxy in Andromeda. First, M-31 is a naked eye object from a reasonably dark site. Interestingly, the photons that we see or collect have been on their way for about 2.2 million years. In other words, long before there was a sentient, cosmically aware species on Earth those photons were making their way here. M-31 is one of if not the most distant naked eye DSO.

Second, M-31 is a so-called sister galaxy, part of the local cluster. The local cluster has two giants -- M-31 and the MWG -- some fair sized sisters such as the SMC and LMC, and M-33 -- and a slew of little elliptical galaxies. (There's an interesting visual of the local cluster here.)

And finally, gravity is bringing our own Milky Way Galaxy and the Andromeda Galaxy together. They are approaching each other at an incredibly fast rate of speed. There's a good chance that they will merge when the rendezvous is finally complete.

Acquisition and Processing
SV115 at f/5.6 on the CGE, SBIG ST2000XCM, 17 subs at 3 minutes, acquired using CCDSOFT v.5, processed in ImagesPlus 3, beta9 and PhotoShop CS2.