December 8
The Dove in the South
Sun Position
The Sun is in Sagittarius, about 23.2 degrees south declination. Northern Hemisphere nights are near their longest of the year; southern nights are near their shortest.
Sky Highlight
Columba the Dove is low in the south for observers at mid-northern latitudes this week, riding above the horizon in the evening hours but requiring a clear southern horizon to see well. From tropical and southern latitudes, Columba rises higher and offers a comfortable view of the constellation's modest stars.
Deep Sky Object
NGC 1851, a compact and luminous globular cluster in Columba, lies about 39,500 light-years away and is one of the richer globulars accessible in December; it appears as a tight, bright ball in small telescopes, and its unusual dual stellar populations have made it a subject of active research.
Featured Star
Phact (α Col) is a B7IVe blue-white subgiant about 261 light-years away that spins rapidly enough to fling material into a circumstellar disk, the lowercase 'e' in its spectral classification denotes this emission-line behavior. The dove's leading light is quietly doing something more dynamic than its appearance suggests.
Around This Date
- December 8, 2010SpaceX launched its Falcon 9 rocket carrying the Dragon capsule on COTS Demo Flight 1, completing the first orbit and controlled splashdown by a commercial spacecraft, opening a new era in commercial spaceflight.
- December 12, 1970NASA's Uhuru satellite, the first orbiting X-ray observatory, launched from San Marco Platform off the coast of Kenya, opening the X-ray sky to systematic survey for the first time.
Phact spins fast and wears a disk no eye can see, the quiet ones are often the most interesting.