The Pinwheel Galaxy (Messier 101) is a face-on galaxy located about 21 million light-years away from the Earth. The galaxy has a diameter of 170,000 light-years. By comparison, the Milky Way has a diameter of 100,000 light years. It has around a trillion stars, a little more than twice the number in the Milky Way. It has a disk mass on the order of 100 billion solar masses, along with a small central bulge of about 3 billion solar masses.
Since I pursue astrophotography, this was my longest imaging project. I collected the photons from this distant world during 3 consecutive nights. The final image presented below is the result of 11 hours of exposure. Unfortunately due to the high moon the conditions were not the best, but I had clear nights after a long period.
After initial setup, the image acquisition was performed completely automated. The here presented image shows the telescope waiting for the imaging session. The roll-off-roof is closed and the telescope is in the horizontal parking position. The roof has to be removed manually but the rest of the process could be controlled from the main house.
Due to the relatively deep image (nearly 11 hours of exposure) some very distant background galaxies are also visible. I could identify some of them using astronomical catalogs and other internet sources. The galaxies marked with blue arrow-heads are located about 1.2 billion light-years away from Earth. The smaller reddish spot marked with red arrow-head is an even more distant galaxy located about 4.4 billion light-years away from Earth. (source: www.ptes.hu) This distance is about at one-third till the edge of the observable universe! These photons, captured by the sensor of my camera a few weeks ago, left this galaxy 4.4 billion years ago - the Earth is 4.6 billion years old!