Bob Moler's Ephemeris Blog

This is Ephemeris for Tuesday, May 16th. Today the Sun will be up for 14 hours and 51 minutes, setting at 9:05, and it will rise tomorrow at 6:12. The Moon, 3 days before new, will rise at 5:08 tomorrow morning.

Regulus is the brightest star in the constellation of Leo, the lion at the bottom of the backward question mark that is the head and mane of Leo. It’s in the southwest at 10 pm. Alluding to the lion’s status in the animal kingdom, Regulus is the little king star. It is dead last in order of brightness of the 21 brightest first magnitude stars, 1/13th the brightness of Sirius the brightest nighttime star, now lost in the evening twilight glow. To the Babylonians it was the king, the 15th of their constellations, that marked the passage of the Sun. Regulus is about 79 light years away, and 288 times the brightness of the sun. It is a rapidly spinning ellipsoid 3 times the sun’s diameter, rotating in just under 16 hours.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.

Addendum

Regulus and Leo and the other stars and planets in the western sky at 11 pm, May 16, 2023. Created using Stellarium.