December 7
The Sword-Foot
Sun Position
The Sun is in Sagittarius, near 23.1 degrees south declination. Northern Hemisphere solar noon sits lower on the horizon than at any other time of year; southern skies have the Sun high and the days long.
Sky Highlight
Orion's Sword hangs below the Belt in fine viewing position this week, containing M42 and the faint M43. For northern observers, the Sword is easily visible above the southern horizon; southern observers see it higher, sword pointing upward.
Deep Sky Object
NGC 1999, a small reflection nebula about 1,500 light-years away in Orion just south of the Sword, contains a distinctive dark 'keyhole' feature, once thought to be a dark cloud blocking background light, it is now understood to be a true hole blown through the nebula by outflows from newborn stars.
Featured Star
Saiph (κ Ori) is a B0.5Ia blue supergiant about 720 light-years away, marking the southeastern foot of Orion. Its spectral type nearly matches Rigel's, but greater distance dims it to a modestly bright star, a wolf in moderate clothing, hiding luminosities far exceeding what its visual brightness suggests.
Around This Date
- December 7, 1972Apollo 17 launched at 12:33 AM Eastern time from Kennedy Space Center, the only nighttime launch of the Apollo program, illuminating Florida's Atlantic coast for hundreds of miles.
- December 7, 1995Galileo fired its orbital insertion burn and became the first spacecraft to orbit Jupiter, beginning detailed study of the planet and its moons Europa, Ganymede, Callisto, and Io.
Saiph looks ordinary from here, the Universe is full of things that only reveal their scale when you know the distance.