Messier 99 is a grand design spiral galaxy in Coma Berenices. Unlike our Milky Way, it does not have a bar structure across the center. It is about 45 million light years away and is part of the large Virgo Cluster of galaxies
Its apparent size is fairly small, only around 5 arc minutes in diameter, making it about a sixth as wide as the full moon.
This is 16h 55m of LRGB data. For all the technical details see astrobin.