June 29
The Pointer's Secret
Sun Position
The Sun is in Cancer, declination near +23.0°. Northern days are still long but the solstice is behind us; southern winter nights remain extended.
Sky Highlight
No major meteor shower peaks today. From the Southern Hemisphere, this is an excellent night to observe the Southern Cross and the nearby Centaurus region, where Hadar (tonight's featured star) and Alpha Centauri stand as the sky's brightest Pointer stars toward the Cross.
Deep Sky Object
Omega Centauri (NGC 5139), a globular cluster about 17,000 light-years away. Omega Centauri is the largest and most massive globular cluster in the Milky Way, containing several million stars and spanning about 150 light-years; it is so massive that it may be the stripped nucleus of a dwarf galaxy swallowed by the Milky Way. Best from southern latitudes and the tropics; from northern mid-latitudes it barely clears the southern horizon in summer.
Featured Star
Hadar (β Cen) is a blue giant (B1III) about 390 light-years away in Centaurus, the second-brightest southern Pointer star alongside Alpha Centauri; it is actually a triple system (two close blue giants orbiting each other, with a third companion) that appears as a single brilliant blue point. Its light left when Shakespeare was still writing.
Around This Date
- June 29, 1995The joint Atlantis-Mir crew conducted transfer operations, marking the first time astronauts from both nations worked together aboard a jointly docked spacecraft.
- June 30, 1908The Tunguska impact event occurred over a remote area of Siberia, when a small asteroid or comet fragment exploded in the atmosphere with energy estimated at 10 to 15 megatons, flattening approximately 2,000 square kilometers of forest.
What looks like one blue star from here is three; the sky rarely shows its full hand.