NGC 1821

NGC 1821 is an irregular galaxy in the constellation Lepus about 170 million ly from Earth. It spans roughly 62,000 ly, about 62% of our Milky Way's width. The light reaching us tonight left it about 170 million years ago.

Because its light is 170 million ly from home, you are seeing NGC 1821 as it looked roughly 170 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).