Tonight’s full moon is the first full moon of spring. The moon is right on the celestial equator.

So much attention at the start of spring is given to the sun when it sits on the celestial equator. Spring arrives, the scientists report, when the sun passes from the southern hemisphere into the northern hemisphere. Tonight the full moon straddles the same equator but at the opposite part of the sky.

The full moon, also called the Worm Moon, is in the zodiacal constellation Virgo. The sun is directly opposite the full moon and it resides on the celestial equator in the zodiacal constellation Pisces. The moon rises as the sun sets.

Often homeowners aren’t precisely sure where east and west are located in relation to their home. There is opportunity for certainty tonight. This being March 21, a day after the first day of spring, is a rare moment when the full moon rises precisely in the east while the sun sets precisely in the west. You won’t see it happen again this year. The next day is on the last day of summer, but it isn’t so perfect as tonight.

The first day of fall occurs on Sept. 22, but the full Harvest Moon is seven days prior.

Planets

Mars and Saturn are our evening planets. The red planet Mars is overhead in the constellation Gemini at dusk and Saturn is rising in the east in the constellation Leo.

M.A.L.