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| Messier 63 |
Constellation: Canes Venatici
Distance: 30 million light years
Equipment: Vixen VC200L with x0.71 focal reducer, SX694, Avalon Linear mount, guiding with Lodestar X2/PHD
Messier 63 (M63, also known as the Sunflower Galaxy) was discovered in 1779 by the French astronomer Pierre Méchain and was the first of 24 objects that Méchain would contribute to Charles Messier’s catalogue.
High overhead on late Spring evenings, M63 is tucked away under the tail of the Great Bear in the obscure constellation of Canes Venatici. It can be seen in binoculars as a small, hazy patch of light or an out-of-focus star. The Stellarium sky map below shows M63’s location.
As seen in the sky from Earth, the galaxy occupies an area of 12.6 by 7.2 arc minutes, which corresponds to a spatial diameter of 98,000 light years. This makes it roughly the same size as the Milky Way, having a mass around 140 billion times that of the Sun.
Messier 63 has a distinctive appearance that gives rise to the “Sunflower” nickname, with a yellowish central disc and a number of short spiral arm segments dotted with starburst regions and dust lanes.
M63 is a prototype for a class of galaxies known as “flocculent spirals". Such galaxies seem to have many spiral arms that appear patchy and discontinuous, although infrared observations indicate that M63 is in fact a two-armed spiral structure.
Messier 63 is one of the members of the M51 Group, a group of gravitationally bound galaxies located in Canes Venatici, named after the brightest member of the group, Messier 51 (the Whirlpool Galaxy).
In 2011, astronomers discovered a tidal stellar stream in the galaxy’s halo. The faint giant arc-loop feature had been detected as early as 1979, but not connected to a minor merger with a dwarf satellite galaxy, disrupted as a result of interaction with M63. The stream of stars originated from the accretion of the smaller galaxy within the last 5 billion years. The fate of the dwarf galaxy is unknown, but the colour of the stars indicates that it was probably a galaxy belonging to the Local Group.
The recent and unprecedented run of overcast weather means that this winter’s nebula season has been pretty much clouded out. I have therefore packed away the refractor and decided to try and go for some galaxies using my ancient Vixen VC200L and a x0.71 focal reducer. I am hoping to capture some of the brighter spring galaxies, using short exposures so that I can complete imaging projects in a single night and not have to hope that I can get two or three clear nights to collect enough data.
This was a test run of the concept and it seemed to go OK. The subs appeared slightly vignetted and there were some horrible dust doughnuts, but a combination of flat fields and Astroart’s gradient removal tool seemed to clean up the worst of it all.
The exposures were not deep enough to clearly reveal M63’s tidal halo referenced above, but it was nice to get enough data for a colour image within three hours.
References:
1) https://www.nasa.gov/feature/goddard/2017/messier-63-the-sunflower-galaxy
2) https://www.cosmotography.com/images/small_ngc5055.html
3) https://www.messier-objects.com/messier-63-sunflower-galaxy/
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