Messier 2

M2, the second entry in Charles Messier's catalogue, is a large bright globular cluster of stars in the constellation of Aquarius. It appears to be a remnant of an old dwarf galaxy, now known as the Gaia Sausage, which merged with the Milky Way around ten billion years ago.

The image above was taken when the camera was being commissioned and, in particular, before the autoguider was working properly. In consequence the stars were slightly trailed. To remedy this the geometrical distortion was measured and used for 20 iterations of Richardson-Lucy deconvolution during post-processing. The stars are now sharp and circular but, unfortunately, the deconvolution produced spurious rings which may be seen around a few of the brightest stars.