NGC 6821

NGC 6821 is a spiral galaxy in the constellation Aquila about 70 million ly from Earth. It spans roughly 21,000 ly, about 21% of our Milky Way's width. The light reaching us tonight left it about 70 million years ago.

Because its light is 70 million ly from home, you are seeing NGC 6821 as it looked roughly 70 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).