Astronomy Picture of the Day . ... Doing their part in the ongoing dance of the planets, Mercury and Venus both reached their greatest elongation or maximum apparent distance from the Sun only a few days ago, on March 29th. ... April Fools Day More Intense On Mars . ... Spanning an angle larger than the Moon, M39's relatively few stars lie only about 800 light years distant toward the constellation of Cygnus. A Prominent Solar Prominence from SOHO . ... Stars and the Bubble Nebula . ... March . ...