M51 and NGC 5194 (Whirlpool Galaxy). At about 23 million light-years from Earth it's estimated diameter is about 75,000 light-years. It is believed a large black hole resides at the galaxy core or center.

M51, 5_16_21_225x30' total-112"30'
That is a nice photo! Glad to see you took it from the side and not the edge.