Ring Galaxy

Ring Galaxies  are a particular type of peculiar galaxy formed when another galaxy passes through the centre of a spiral or lenticular galaxy, creating the ring shape. The ring is fairly similar in composition to a spiral arm, whereas the bulge is identical to the bulges of spiral galaxies or elliptical galaxies.

Habitability of such a galaxy would depend on whether a particular star system lies in the bulge (not habitable), the ring (dangerous) or somewhere in between (possibly habitable). The night sky would resemble that of a planet in a spiral galaxy, but may differ, again depending on the position of the observer in the galaxy.

Ring galaxies are designated with a (r).

Examples include the famous Hoag’s Object, the Cartwheel Galaxy and AM 0644-741.

Worldbuilding in Practice
"The Ripple Galaxy, named for its ripple-like ring structure, is a barred lenticular galaxy and a ring galaxy, classified SB0(r). It is about 1800 parsecs across and contains roughly 30 billion stars. It is incredibly beautiful to observe and is the second largest object (apart from any nearby planets or suns) in the night sky when observed from Karnak, second only to Hathor, visible in most parts to the naked eye."