NGC 5107 and 5112 are a pair of blue, non interacting, spiral galaxies. Red shift puts them at about 55 million light years. Tully-Fisher measurements of 5107 range from 45 to 76 million light-years while those for NGC 5112 cover an even wider range of 59 to 101 million light-years. While that makes it possible they aren't at all close to each other I have to think their similar redshift is no coincidence and they are a related pair. It was discovered by William Herschel on March 17,l 1787. It's not in either H400 program

NGC 5107 is classed as SB(s)d? by NED and SBcd by the NGC project. The question mark indicates some uncertainty about the wide arm (d) classification. It certainly is hard to tell from our perspective. It has some interesting knots in the arms northwest of the core that are brighter than the galaxy's core. I'd love to see this one more face on.

NGC 5112 is seen nearly face on. Its arm structure is rather disorganized. NED classes it as SB(rs)cd while the NGC project says SBc. Even face on there is some debate over the c or d classification of the arm structure. William Herschel found this one the same night as NGC 5107. It isn't in either program either.

All redshift has been converted to "light travel time" distances using NED's 5-year WMAP calculations. That is the time the light has taken to reach us since it left the object. The object was closer when the light was emitted and is currently further away. The universe's expansion all those billions of years causes the light to have to travel longer and further than it would have in a static universe. In that time the object has been carried much further away. In fact for those with a very high redshift they are currently so distant the light they emit "today" will never reach us as they are being carried away at a speed greater than the speed of light.

14" LX200R @ f/10, L=6x10' RB=3x10'x3 G=2x10'x3, STL-11000XM, Paramount ME