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About the Galaxy

M106, also known as NGC 4258, is a striking spiral galaxy located approximately 22 to 25 million light-years away in the constellation Canes Venatici. Distinguished by its Seyfert II nucleus, M106 is an active galaxy with a supermassive black hole at its center, emitting strong radio waves and X-rays. Its distinctive features include prominent spiral arms, an extensive system of dark dust lanes, and regions of intense star formation. M106 is particularly notable for its anomalous arms, which appear to be jets of gas and dust ejected from the central regions, likely influenced by interactions with the supermassive black hole. These features make M106 an intriguing object of study for astronomers seeking to understand the complex dynamics of galaxy evolution and active galactic nuclei.


This proved to be a very frustrating target to shoot. I had chosen it because a few excellent astrophotographers I follow on Twitter had posted amazing shots of the galaxy, and I wanted to try my hand at it. However, I didn’t realize it was much fainter than the previous galaxies I’ve shot. The core is quite bright, but the halo of stars around it, which makes it such an interesting galaxy, is very faint and took a lot of subframes to properly expose.

One thing I tried and failed at with this image was incorporating flat frames. I don’t typically use flats as I don’t have a good setup yet to acquire them, but with the edges of this galaxy being so dim, I wanted to try it. The flats I got seemed to be of decent quality, but when integrating them into the image, I found they actually worsened the image quality. After some troubleshooting, I think the issue ended up being poor calibration of the flats with dark frames. Because I’m shooting with a DSLR, it’s very sensitive to thermal noise. To properly calibrate the flats, I should be taking darks at the same time and with the same exposure as the flats to ensure the camera temperature is consistent. Since I didn’t do this, the thermal noise pattern didn’t match well, and the flats did not calibrate properly. I ended up not using the flats in the final shot, but I have plans to build a rig to acquire flats automatically in the future, so I hope to make it part of my normal imaging setup.

Image Details

  • Light Frames: 657 frames, 60 seconds exposure per frame, 1600 ISO
  • Dark Frames: 100 frames
  • Bias Frames: 50
  • Flat Frames: None

Pixinsight Workflow

  • Photometric Color Calibration
  • Dynamic Background Extraction
  • BlurXTerminator
  • NoiseXTerminator
  • Histogram Transformation
  • Curves Transformation