Messier 108 - Surfboard Galaxy
The barred spiral Messier 108 was discovered in February 1781 by Pierre Méchain at the same time as Messier 97. With a brightness of 9.9mag and
an apparent size of 8.6x2.4', it is located in the constellation “Big Dipper” (UMa) and is also known as the “Surfboard Galaxy” because of its appearance.
Its distance is given as around 41 million light-years, but there are also other estimates. The diameter of the galaxy is around 100,000 light-years - so it
is almost as large as our Milky Way.
The total mass is estimated to be 125 billion solar masses, while the true luminosity is 15 billion suns. This corresponds to an absolute magnitude of
M= -20.6mag. Many HII and starburst regions can be recognized in the corpus of the galaxy, as well as dark dust clouds. Around 290 globular clusters
have been detected in the halo, while a supermassive black hole (SMBH) with 24 million solar masses has been found in the center.
So far, only 2 supernovae have been observed in Messier 108: SN1963B with a maximum brightness of 13.9mag and SN2023dbc at 17mag.
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Messier 108 offers a wonderful sight in my 20” Dobsonian. :))
At a magnification of 270x, the galaxy appears as a patchwork of bright and dark areas. In addition, several HII regions can be seen, some of which contain
a stellar core (SSC?).
There is a brighter bar in the center. Some of the dust bands are very prominent, especially in the western part of the galaxy. In addition, three stars can be
seen in the halo, including a bright one near the center that could easily be mistaken for a supernova.
