Home > Observing, The Moon > 02/15/2021 – Ephemeris – For a few months the Earth had two moons

02/15/2021 – Ephemeris – For a few months the Earth had two moons

February 15, 2021

This is Ephemeris for President’s Day, Monday, February 15th. Today the Sun will be up for 10 hours and 29 minutes, setting at 6:11, and it will rise tomorrow at 7:41. The Moon, halfway from new to first quarter, will set at 10:22 this evening.

The Moon tonight is a waxing crescent. A four-day-old moon. In binoculars, it shows one complete lunar sea, the Sea of Crises, or if seen on a moon map, Mare Crisium. Speaking of the Moon, for the last few months the Earth had a second moon, with the asteroid designation 2020 SO. This was traveling slowly behind the Earth, and is suspected to be the Centaur upper stage of the Surveyor 2 lunar landing craft launched in 1966. It ended up orbiting the Sun. 2020 SO took a loop and a half around the Earth and is heading back in solar orbit. The ascent stage, Snoopy, from Apollo 10 is also in solar orbit. I hope one day it can be captured on a close approach and brought back to the Earth or the Moon for display. That would be really cool!

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


Binocular Moon

The moon as it might appear tonight, at 8 pm, February 15, 2021. Mare Crisium is the round gray sea near the lower right edge. Created using Stellarium.

Animation of object 2020 SO as it encounters the Earth. Also shown is the orbit of the Moon and geostationary satellites. Credit: NASA/JPL – Caltech.


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