Nautilus Galaxy NGC 772

Around 200,000 light years in diameter, NGC 772 is twice the size of the Milky Way Galaxy, and is surrounded by several satellite galaxies – including the dwarf elliptical, NGC 770 – whose tidal forces on the larger galaxy have likely caused the emergence of a single elongated outer spiral arm that is much more developed than the others arms. Halton Arp includes NGC 772 in his Atlas of Peculiar Galaxies as Arp 78, where it is described as a "Spiral galaxy with a small high-surface brightness companion".

This image was take on December 19 2014 in the  Big Cypress National Preserve under semi clear conditions and no moon. 

Image details 

LRGB combine in Pixinsight 
LUM 12x600sec, RGB 12x300 sec
Scope: Vixen VC200L f/9 200mm
Mount: Altlas Pro 

CCD ST-8300