August 15
Three Stars at the Tail
Sun Position
The Sun is in late Leo at approximately +13° declination. The Northern Hemisphere summer is firmly in its second half; Southern Hemisphere observers notice the darkest mornings are behind them.
Sky Highlight
Mid-August brings the Milky Way's richest fields to the meridian at a reasonable hour, the dense star clouds in Sagittarius and Scorpius are due south around 9-10 PM local time for northern mid-latitude observers, overhead or near-overhead for Southern Hemisphere observers. A steady, dark sky tonight reveals the galaxy's own structure.
Deep Sky Object
M20, the Trifid Nebula in Sagittarius, is an unusual emission and reflection nebula divided into three lobes by dark dust lanes, lying about 5,200 light-years away. It is best seen from the Southern Hemisphere or from low northern latitudes where Sagittarius rises higher. Through a telescope the dark lanes that split the glowing gas are its defining feature.
Featured Star
Shaula, the lambda Scorpii system at the scorpion's sting, is roughly 700 light-years away and consists of at least three stellar components, with the primary being a B1.5IV blue subgiant. The name comes from Arabic for 'the raised tail'. It marks the final bright point of Scorpius before the constellation plunges below the horizon for northern observers.
Around This Date
- August 12, 1877Asaph Hall discovered Deimos while conducting his systematic search for Martian satellites, a search he had nearly abandoned the previous night at his wife's encouragement to continue.
- August 20, 1977Voyager 2 launched toward the outer Solar System, carrying the Golden Record, a message from Earth intended for any interstellar finder, containing sounds, music, and images of life on this planet.
Three stars masquerading as one point at the tip of a mythological tail, astronomy has a way of finding complexity exactly where the story says there should be only one thing.