Mottled Galaxies

I enjoyed some wonderful galaxy observing in my front yard Tuesday night. It only amounted to 3 galaxies: M49, M61 and M99. But what a sight they were. I’ve learned that despite being inside the East-Flagstaff Industrial Light Circus, once objects have cleared about 45 degrees elevation, I’ve got the high-altitude/low aerosol atmosphere on my side. Spotting objects is rarely a problem, and it turns out, with some effort, a satisfying amount of detail can be examined too.

First glance views of M61 and M99 showed fairly flat, smooth discs. About what I expected from my location, but spending time with them paid off. They started to convey diffuse mottling after a while. If you ever observe a galaxy* and make a note that it was mottled, don’t stop there! Diffuse, subtle, intermittent mottling can be very hard to examine, but the fact that you are detecting an irregularity in brightness means that conditions are ripe to allow you to start pinning down structure.

Go for the more consistent splotches first. On what side of the core do they appear? Do they engulf the core, do they hug it, or are they detached from it? Are they wide or narrow? Spend a lot of eyepiece time and averted vision and let the flickering appearances build up enough to give you an impression of where that extra bit of light resides. Mark it on your sketch, and you’ve got a starting point. Look for any other irregularities. How do they relate to the core and the patch(es) you have already seen?

Both spiral galaxies I observed that night yielded details that showed brighter areas of their spiral structure (M99 was especially impressive, and it is on my hit list for an extra helping during my next dark sky visit). My wife was watching Tornado Intercept on National Geographic while I was observing. I couldn’t help laughing a bit, because I noticed myself resonating with the storm chasers hollering about seeing two tornadoes on the ground at once. At the same time, I was celebrating seeing at least two spiral arms in each of these magnificent galaxies. It’s a peculiar harmony of Geek Synchronicity.

I’ll have the sketches and observing reports up before long. Meanwhile, give those galaxies everything you’ve got!

* or any other extended object for that matter.

Leave a Reply

Your email address will not be published.