M97: The Owl nebula

This was my first ever narrowband image. Picture was taken in the middle of April when there was only 12min of astronomical darkness left here in Southern Finland. Total exposure was about 4hrs (SIIHaOIII).

I'm not too satisfied with this picture! I took too short and/or too few subexposures to get a good image. I didn't realize that collected data through narrowband filters is much weaker than through color filters.