Messier 99 – The Coma Pinwheel

Messier 99 (M99), also known as the Coma Pinwheel or Virgo Cluster Pinwheel, is a galaxy in Coma Berenices. The galaxy is a member of the Virgo Cluster. It has an apparent magnitude of 10.4 and lies at a distance of 55.7 million light years from Earth. Messier 99 is a grand design spiral, completely unbarred and with two giant spiral arms. One of the spiral arms is normal and the other appears distorted. M99 is thus slightly asymmetric in shape, with the nucleus shifted from the galaxy’s centre, likely as a result of interactions with other galaxies in the Virgo Cluster, more specifically with the lenticular galaxy NGC 4262 about 280 million years ago. As a result of the encounter, the star forming rate in M99 is three times greater than in other galaxies of similar type.

Crop of Messier 99


Messier 99 & NGC 4302 and NGC 4298 (R)

Telescope: 16″ f3.75 Dream Scope
Camera: FLI ML16803
Mount: ASA DDM85
Exposure: 4.5 hours (24x300s L + 3x9x300s RGB)
Date: March 2020
Location: Southern Alps, France

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