A famous triplet in Leo: M65, M66 and NGC 3628
The 3 spiral galaxies which form the M66 group exhibit marked differences. M66 is actively forming new stars but M65 looks very quiet. The differences are emphasized here with the use of a Halpha narrow band filter in addition to the usual LRGB ones. The red spots in M66 are the active HII regions. This activity results probably from a previous encounter with NGC 3628 (on the right top corner)
C11-HD and STL 11km on G11 mount.
Total exposure: 8hours 40' in 10' subs
2 hours in luminance binned 1x1
3 hours 40' in Halpha binned 2x2
1 hour for each RGB filter binned 2x2