M51, the Whirlpool galaxy, is great example of a spiral galaxy. The spiral arms reaching out are star formation areas, compressing hydrogen gas and creating new star clusters. It is located near Alkaid, the outermost star of the Big Dipper’s handle.
M51 consists of two galaxies; M51a (NGC 5194) and M51B (NGC 5195). M51A is the large, main structure. M51B is the smaller galaxy at the spiral arm’s end. The smaller M51B has been slowly gliding behind M51A for hundreds of millions of years. One theory for the prominent whirlpool structure is that the smaller galaxy is causing tidal forces that trigger new star formation.
Since 1994, three supernovae have been observed in this galaxy. The Whirlpool is 23 million light years from earth, and 76,000 light years across. It will be a long flight to visit this one.
This is my attempt from the previous year. I used a DSLR for this image. I have since learned new processing techniques, and continue to do so. There is always something new to learn in Astrophotography.
The latest image was taken using data from multiple nights throughout March. I used an ASI1600mm monochrome camera attached to a Canon 500mm f/4L IS II lens. The equipment was mounted on the Skywatcher EQ6r-Pro equatorial mount and controlled remotely through a Raspberry Pi running Stellarmate software.
This is an HaRGB image; A filter wheel with red, green, and blue, filters was used to get the color data. A Hydrogen-alpha filter was used to bring out additional detail in the red color. The images were stacked and processed using PixInsight. The data was gathered over several nights before clouds set in. I processed the data I had at the time and the result is below. I had significantly more green data due to clouds coming in during the evenings when I was collecting red and blue images.
After a couple weeks the clouds lifted enough to get some additional red and blue images. I re-processed the image, adding in the additional data. I was able to bring out some additional detail and I removed the green tint around the galaxy. This did make some of the dust surrounding the galaxy dimmer, but I think it works. I left the image slightly with a slightly wider field of view to show the two galaxies near the lower left corner; NGC 5169 in the lower left, and above and to the right of it is IC 4263. I am sure I will be doing more imaging of the Whirlpool!
