For two years I’ve been wooing a real beauty, without success until now.
It’s the lovely spiral galaxy NGC7331, a good target in the autumn, riding high in the constellation Pegasus.
The first time I tried, in September 2009, I imaged it from our backyard. Salt Lake City’s heavy light pollution intruded and the galaxy’s portrait was hideous, a greenish-toned mess with multiple “dust doughnut” flaws that showed up all too clearly in the glare. Later in 2009 I tried from Kanab but the exposures were too short.
On the morning of Aug. 14, 2010, I took another chance at the ORV recreation area called Knolls, Tooele County. My notes from that attempt:
“I found my target for the night, NGC7331, right off the bat by syncing on a nearby star, Matar, a corner point in Pegasus. I got it centered and then had the Meade guide camera lock onto a target and begin guiding. Next I was going to focus the main camera. … Then a hurricane of wind hit. I wasn’t able to focus adequately and certainly was precluded from any serious imaging. I took several focus views at 320 seconds each, just to see if the guider worked, and they seemed identical, though of course horribly blurry.”
The wind, which I estimated at 30 mph, kept up all night, ruining any chance at astrophotography.
Not one to give up easily, I tried at Lakeside, Tooele County, on the morning of Sept. 25 this year. In a total of 48 minutes exposure for luminosity (16 images of 3 minutes each), I collected enough photons for an acceptable view. However, it was a little anemic and the color exposures were too short to do it justice.
Returning to the site to work through the night of Sept. 26-27, I took images of NGC7217 (discussed in the previous blog). In the early morning I aimed my scope at NGC7331 and aligned it to closely match the pictures I had taken two mornings before. It soaked up light for about 4 1/2 hours.
Not all the frames were usable, but most were. When I digitally combined them with the Sept. 25 exposures, the galaxy looked good.
[View of NGC7331 taken on the mornings of Sept. 25 and 27 at Lakeside, Tooele County; total exposure about 5 hours. For a larger view, click HERE. Photo by Joe Bauman]
According to the NASA Astronomy Picture of the Day site for Oct. 22, 2008, this beautiful spiral galaxy is about 50 million light-years distant. The caption notes that it is about the size of our own Milky Way Galaxy.
It’s called a member of the Deer Lick Group of galaxies, but its membership is only accidental, a result of happening to align between our galaxy and the rest of the Deer Lick bunch. They are really about 10 times farther away, according to APOD.
In my view, two of those more distant galaxies show up just “above” NGC7331, the fancy spiral galaxy NGC7337 on the upper left and NGC7335 on the upper right.
A scientific paper published in 1996 said the central disk of the big galaxy in our view, NGC7331, rotates in an opposite direction to the rest of the galaxy. But the next year another paper disagreed.