Andromeda Galaxy

The first target with my new NexDome observatory was Andromeda. Given that it is so close to us and so large in the sky, I only did a small part of it. My field of view is only about 1 degree, while Andromeda is over three degrees long. If you’re in the Northern hemisphere, it is just now rising in the east after dusk. Under good skies, you can see it with the naked eye. A pair of binoculars can bring it out in light pollution.

I spent three nights of about 7 hours each on it. I had a few problems but managed 200 good frames, totaling a little over 13 hours. I could go for more, but I have some equipment changes I want to make, so I need to finish this target. The target is also so bright that noise wasn’t a big problem with so little data.

The dome mostly worked out well, except the first night where it partially occluded the scope after the meridian flip. The other two nights, it tracked the scope very well. I was having a good bit of trouble with guiding, and I think it is due to the cheap guide scope I am using. It is hard to focus, and I think it has significant chromatic aberration, which leads to bloated stars that regularly change profile due to seeing. My next step is “off axis guiding” to improve the guiding as well as differential flexure that I noticed throughout the nights from the poor guidescope mounting. Dew also made a comeback, so I’ll have to figure out something stronger to take care of that.

Overall, I absolutely loved the result!

As you can see, we can pick out so much more detail and structure within Andromeda because it is so much closer to us than the other galaxies that I image. Andromeda is only about 2.5 million light years away, and it is hurtling right towards us. The white ball to the bottom right is M32, a dwarf galaxy that orbits Andromeda.

The blue areas of Andromeda contain younger stars, and you can see many clumps of them throughout. These would be similar to star clusters that we see in our galaxy. The reddish areas near the center contain older stars. The core of the galaxy is just out of frame to the right side. The dark stripes are dust lanes. Zoom in, and you can see many red splotches in the galaxy. These are nebula, hydrogen-rich gas areas that will lead to star formation.

I’m not sure what the line is in the upper right corner. It’s definitely part of the data. I think it is a diffraction spike from something extremely bright, possibly from the core of the galaxy.