November 24
Aldebaran Overhead
Sun Position
The Sun is in Sagittarius at about -21° declination. Northern Hemisphere has its earliest sunsets of the year around this time (the exact date varies by latitude). Southern Hemisphere is in full summer.
Sky Highlight
From mid-northern latitudes, Taurus is now rising in the early evening and the Hyades and Pleiades are prominent by 8 p.m. The Hyades cluster, the nearest open cluster to Earth at about 150 light-years, contains hundreds of stars spread over a wide area around Aldebaran, though Aldebaran itself is not a member, lying at half the distance.
Deep Sky Object
The Hyades, open cluster in Taurus, about 150 light-years away and the nearest open cluster to the solar system. The cluster's V-shaped asterism forms the bull's face, and it has been used as a distance calibrator for the entire extragalactic distance scale. Aldebaran appears to sit in it but is actually an unrelated foreground star. Excellent in binoculars from both hemispheres.
Featured Star
Aldebaran (α Tauri) is a red giant 65.3 light-years away, spectral class K5III. It's one of the nearest bright giants to Earth, close enough that the Hipparcos satellite measured its angular diameter directly. Its orange-red color in the bull's eye position is a naked-eye pleasure in November evenings, and it has been used for lunar occultation timing for centuries.
Around This Date
- November 24, 1639Jeremiah Horrocks and William Crabtree independently observed the first confirmed transit of Venus, a landmark in solar system measurement.
- November 27, 1971Mars 2's descent module struck Mars, the first spacecraft to reach the Martian surface, though it failed to land intact.
Aldebaran sits in the bull's eye like it belongs to the Hyades, but it's a stranger, half the distance, the same direction, just passing through.