IC 3945

IC 3945 is a spiral galaxy in the constellation Canes Venatici about 503 million ly from Earth. It spans roughly 72,000 ly, about 72% of our Milky Way's width. The light reaching us tonight left it about 503 million years ago.

Because its light is 503 million ly from home, you are seeing IC 3945 as it looked roughly 503 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). Distance computed by gravityfinder from redshift via Hubble's law (H0 = 70 km/s/Mpc).