February 15
The Uncertain Name
Sun Position
The Sun is in Aquarius near +8ยฐ declination. Northern mid-latitude daylight runs about 11 hours; southern hemisphere days continue to shorten.
Sky Highlight
On February 15, 2013, the Chelyabinsk superbolide entered the atmosphere over Russia, releasing energy equivalent to roughly 400โ500 kilotons and injuring approximately 1,500 people. This is the largest recorded airburst since Tunguska (1908), a real annual reminder of the ongoing impact hazard.
Deep Sky Object
M41, an open cluster about 2,300 light-years away. A large, bright open cluster in Canis Major possibly mentioned by Aristotle around 325 BCE as a 'cloudy spot', if so, it may be the oldest recorded deep-sky observation. Well-placed for both hemispheres in February; southern observers see it higher.
Featured Star
Muliphein (ฮณ CMa) is a blue-white bright giant 402 light-years away, spectral class B8II, whose name's origin has been disputed for centuries with no settled etymology. A star whose name nobody can fully explain, it stands in the great dog's outline, anonymous in the best way.
Around This Date
- February 15, 2013A superbolide exploded over Chelyabinsk, Russia, the most energetic recorded atmospheric impact since Tunguska, releasing an estimated 400โ500 kilotons and injuring roughly 1,500 people from shockwave-broken windows.
- February 15, 1564Galileo Galilei was born in Pisa, the astronomer who became one of the first to use a telescope systematically for astronomical observation and defend Copernican heliocentrism.
Galileo's birthday and Chelyabinsk's anniversary: February 15 is a good day to look up.