Messier 105 is the elliptical galaxy at the top of the image. To the bottom right is NGC 3384 and to the bottom left is NGC 3389. M105 is also cataloged as NGC 3379. M105 was discovered by Pierre Méchain in 1781 and sent to Messier for his catalog but Messier did not include them because he never verified them. It wasn’t included until later. It’s not clear to me why the other two galaxies were not listed. My assumption is they were too faint to see visually but that’s really just speculation.

M105 is 36.6 million light years away in the constellation of Leo. NGC 3384 is slightly closer at 35.1 million light years and it wasn’t discovered until 1784 by William Herschel. Wikipedia also says it’s an elliptical galaxy. NGC 3389 is a spiral galaxy but it’s about twice as far away at about 72 million light years.

This is 23h 50m of HaLRGB data. For all the technical details see astrobin.