May 19
The Heart of the Scorpion
Sun Position
The Sun is in Taurus at about +20.1° declination. Late May evenings in the Northern Hemisphere are warm; twilight lingers until 10 PM or later at higher latitudes. Southern observers look into clear, dark autumn skies.
Sky Highlight
Antares, featured tonight, begins its annual season of evening prominence. In late May and June it rises in the southeast at a convenient hour for southern and equatorial observers, and low in the south for mid-northern latitudes. Its ruddy color makes it unmistakable, historically leading to confusion with Mars, which is precisely where its name comes from.
Deep Sky Object
M80 (NGC 6093), globular cluster in Scorpius, about 32,600 light-years away. One of the densest globular clusters in the Milky Way, M80 became notable in 1860 when a nova was observed within it, an unusually bright stellar event inside a globular cluster. Well-placed for southern and equatorial observers by late evening; northern observers see it low in the south.
Featured Star
Antares (α Scorpii) is a red supergiant 550 light-years away, spectral class M1.5Iab-b, so large that if placed at the center of our solar system it would engulf the orbit of Mars. Its name means 'rival of Ares' (Mars) in Greek, a reference to the similar red hue and brightness that can cause confusion. It is one of the sky's most certain future supernovae, though that future is likely millions of years distant.
Around This Date
- May 19, 1910Earth passed through the ion tail of Halley's Comet; despite mass anxieties about cyanogen poisoning, no measurable effect on the atmosphere was observed.
- May 20, 1990The Hubble Space Telescope returned its first test images from orbit, which quickly revealed the spherical aberration in the primary mirror that would require a servicing mission to correct.
If the scorpion's heart goes supernova, we will see it in daylight, but not yet.