IC 51

IC 51 is a lenticular galaxy in the constellation Cetus about 80 million ly from Earth. It spans roughly 40,000 ly, about 40% of our Milky Way's width. The light reaching us tonight left it about 80 million years ago.

Because its light is 80 million ly from home, you are seeing IC 51 as it looked roughly 80 million years ago. The photons left before that much of history had passed, and are only now reaching us. This distance is estimated from the galaxy's redshift, so the lookback time is approximate.

Source: structural data (position, morphology, brightness, redshift) from OpenNGC (CC BY-SA). Recession velocity from RC3 (de Vaucouleurs et al. 1991, via NASA/HEASARC, public domain). Distance computed by gravityfinder from redshift via Hubble's law (H0 = 70 km/s/Mpc).