The majestic Winter Circle isn't a constellation. This giant circle - or hexagon - is an asterism, or a pattern made up of stars from several constellations.
NASA's Voyager 2 confirmed the discovery of Neptune's rings on August 22, 1989, when it took images of a faint, continuous ring system around the planet.
On this date in 1877, astronomer Asaph Hall discovered a moon for Mars: Phobos, the larger of 2 moons. He discovered the other moon, Deimos, later that year.
A conjunction is when 2 objects share the same right ascension. The Jupiter-Mercury conjunction on August 15 is the next one. Look for them before sunrise.
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