This time of the year is perfect to observe the spectacular face-on spiral M101 or Pinwheel galaxy.  At nearly twice the size of the Milky Way and containing at least an estimated trillion stars, M101 is the second largest galaxy of the Messier catalogue and certainly one of the highlights of the spring galaxy season.

A loosely bound cluster of galaxies known as the M101 Group, primarily located in the Ursa Major constellation, is also dominated by the Pinwheel Galaxy, which moreover, is considered to form part of a larger structure within the Virgo Supercluster.  Many of the other galaxies in this group are companions to M101, orbiting and interacting with it gravitationally.

Despite its size, M101 is challenging for my William Optics GT81, though I did manage a reasonable image in March 2019.  On this occasion using nearly 17 hours of data from the much larger MOANA 10” Newtonian based at the Dark Sky Observatory in Texas, USA, the resulting image shows the galaxy’s beauty to good effect.

Footnote & credit: Following a recent knee replacement I’m currently unable to set-up and use my astronomy equipment, fortunately I’m still able to continue processing using the excellent public amateur data from the MOANA project located near Fort Davis, Texas  https://erellaz.com/moana/. Many thanks to its creator Elleraz.