M63, the Sunflower Galaxy (5-19-09)

This was the other target on 5-19 besides M109. M63 is between 20 and 37 million light years away and is in the same group as M51. The two are fairly close together in the sky.

What impressed me about M63 is the long cloud of dust across the lower left. The dust does not appear to be following the same circular pattern around the center of the galaxy but rather lies in a straight line tangent to it. The dust lane is just visible in this image as a wide, jagged, dark line running diagonally along the left side of the galaxy. It seems odd to me that it appears to run diagonally and straight. The direction makes it seem that the dust lane is not part of the galaxy but merely crossing by it. In very deep images, such as this one from Tony Hallas, one can see stars forming at the right end of the dust lane on what would be near the outer edge of the galaxy. What's going on here? I am not sure, but notice that Hallas's image also shows loops and filaments of star formation all around the edge of the galaxy and not all of them are in the galaxy's plane. I suppose that M63 is still growing, and as it takes in matter from surrounding directions, not all of it flows evenly and directly into the galaxy's plane. Some of it is still being integrated. This would explain the large and relatively straight dustlane.

I imaged M51 and M63 on consecutive nights partly because each passes the meridian at about the same time. I could not image both in the same night, but both really ought to be done around the same time of year. This image is 148x30" through the Vixen R135S with the Atik 16, unguided. Processed almost entirely in Nebulosity, with a few touchups in PSE7.