Hi all, here is an image I took in middle of November and middle of December on a couple of relatively clear nights. I say relatively because I ended up not using about 40% of the images, which is a huge loss! The images I lost were due to clouds or some other sky deterioration issue. I don't do active guiding which makes my imaging pretty much hands off, but this also insulates me from whether there are clouds or other things happening which are reducing the image quality. I had periodic cloud cover in about 40% of my images, bad enough for them to be rejected.
So hope to capture more data for this, but for now this is what I have.
Andromeda, a spiral galaxy, is our nearest neighbor galaxy at 2.5 million light years distant and 150 light years in diameter. If you could look at our own galaxy from 2.5 million light years away, it might look very similar. The overall mass of M31, or Andromeda, is about 1 Trillion solar masses, which is either about the same or 25-50% more than our own galaxy depending on what literature you look at which means it's just a rough estimate.
Also in the image are M32 a dwarf elliptical galaxy just west of M31's core in my image (actually 22' south) and then M110, just southeast of M31 in my image. M32 is tiny compared to M31 and is only 6500ly in diameter but it's core is similar in mass to M31. Given the distance of M31 and M32 are close on a galactic scale, they've undoubtedly interacted with each other. M110, another dwarf elliptical galaxy, is about twice the diameter of M32 at 12,000 ly and a little farther away at 2.7 million ly distant. Given the proximity to M31, M110 also interacts gravitationaly with M31.
This was imaged with a TEC140 APO reduced to 704mm with an Astro-Physics QuadTCC reducer/corrector on an Astro-physics 1100GTO mount with encoders. The camera is a full frame ASI6200 mono camera with 60M pixels used with Chroma RGB and 3nm Ha filters. I didn't actively guide and instead create a sky model which corrects for any atmospheric refraction, flexture of the system or inaccuracy in my polar alignment. The image scale is 1.1 arc-seconds/pixel. I captured 5.25 hours of Lum, 2 hours of each of R G and B and 3 hours of Hydrogen Alpha. I ended up using only 3.4 hours of Luminance, and 1.5 hour each of RG and B and the full 3 hours of Ha. This reminds me of why I like shooting narrow band, as it is less sensitive to all of the bad weather we have.
I processed the image in Pixinsight with a little editing in photoshop afterwards. I hope to capture more data this year or next.
Constructive feedback is always welcome.
Beautiful capture, Terri, in spite of having to throw some subs away! I love the subtle Ha in the galaxy, the natural star color, and the deep contrast in the spiral arms. Super job!
Greg
@greg-erianne Thanks Greg! I've noticed that the most popular M31s on astrobin are painted in color. I guess that's a style i can't get used to.
Terri
Yes, nicely done. I'm a fan of the more natural, more subdued look for galaxies as well. I'm amazed that you could retain the cores of all 3 galaxies as star-like and not compromise the central regions.
I'm curious what a slightly darker background would look like. I know, at least with my DSLR images, it's hard to retain a nice gradation with a darker background. Though that may mostly be due to not having more that 2-3 hours of data and using a broadband LP filter.
@pwalker Thank you Paul.. didn't see a notification. Maybe you'll not like my next version. I didn't believe the muddy color real and reprocessed it entirely and saturated my image before stretching. This held on to much more color.
Here's an update to my image. I wanted natural colors so no color painting here, but didn't believe the chocolate color natural. So I searched for a processing solution and found one on cloudy nights. In this case I did saturation before stretching and stretched less. Does it work better? I could have upped the saturation more like some images, but kept it mostly as stretched, in fact did not saturate after stretching.. too much, too little?
One more thing I did, is combine my L with RGB in the LAB space. So I replaced the L in the LAB created from RGB, with my luminance data.
I can clearly use more data to get the far outskirts in my luminance a little better... next year.
@terri I think you made an improvement, Terri! I liked your original one, but I can see more detail in the reprocessed image with the increased luminance. Nice job bringing out the extra detail. 🙂
Greg
@terri I think you made an improvement, Terri! I liked your original one, but I can see more detail in the reprocessed image with the increased luminance. Nice job bringing out the extra detail. 🙂
Greg
Thanks Greg, I didn't realize I ended up with more detail, but I did want to get the color maybe more neutral and less muddy. I'll take the detail though!
T
@terri Wow -I think they both look amazing - one maybe more natural but I'd be hard pressed to pick. Inspiring!
@terri I think the detail in the spiral arms/dust lanes is definitely more apparent, Terri! I also think the Ha areas stand out much more prominently, especially those on the periphery. Nice!
Greg
While the first one looks more "natural" the remake has more pop without being over processed. I too like them both though I find the 2nd more aesthetically pleasing.
A very minor observation involves the 2 reddish stars to the upper right that was not immediately noticeable. There seems to be a slight darkening of the background with a slightly reddish halo around them. Looks like some kind of processing artifact that only affects those 2 stars. If I look very carefully I do see the same thing on the other bright stars. On the first image I can see a very faint reddish halo, maybe do to a little bit of haze in the sky at the time. Looks like a large scale contrast enhancement was applied that makes the galaxy stand out from the background better but which also "enhanced" the slight halo around the very brightest star. Maybe the saturation before stretching contributed to this. Maybe a little less saturation before stretching and additional saturation after. Just a thought. Sometimes I have found things like doing stretching in multiple steps comes out a little better than doing it in one step.
Still a great image!
