Messier 61 - Spiral Galaxy
Messier 61 is located at a distance of 45...60 million light-years and, despite the fairly inaccurate distance, it most likely belongs to the
well-known Virgo cluster, which contains between 1300 and 2000 galaxies. It was discovered in May 1779 by Barnaba Oriani - 6 days
before it was also found by Charles Messier. The galaxy has an apparent magnitude of 9.3mag and a size of 6.5'x5.9' arcminutes.
The diameter of the spiral galaxy of Hubble type "SABbc" is about 100,000 light-years. It also belongs to the group of "starburst galaxies",
because in the center there is a massive young star cluster with an age of 4 million years and a mass of 100,000 solar masses. There are
also many HII regions and star forming areas in the spiral arms. Messier 61 has an active galactic nucleus (AGN) and directly in the
center lurks a supermassive black hole (SMBH) with 5 million solar masses.
So far 8 supernovae have been observed, the last one was "SN 2020jfo" with a brightness of 16.0mag and type II.
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With 20" aperture the sight is absolutely fascinating. At a magnification of 270x you can see a very bright stellar nucleus in the
center - which is not surprising, because Messier 61 has a so called AGN, an active galactic nucleus. To see this in the telescope
is impressive.
The bright spiral arms are quite easy to see with indirect vision, as well as the dark gaps in between. The southern arm seemed
brighter and more defined than the other two. Looking closely, you can see a brighter spot on the northern arm, probably an
HII region.
If you are in the Virgo supercluster, you should definitely stop by Messier 61. It is worth it!
