The long-awaited (?) arrival of spring

The seasons they are a-changing. We know that Friday, March 20, is the long-awaited first day of spring, or the vernal equinox, but that is not all that is changing. We will be getting a whole new set of constellations to look at.

On Friday, the Sun will cross the celestial equator from south to north giving us an equinox, or supposedly equal day and night all around the world, which is what the word "equinox" means, equal day and equal night.

Because of that pesky 23.5 degree tilt of Earth's axis in the winter the northern hemisphere tilts away from the Sun and in summer we tilt toward it (except for our good friends south of the equator it is exactly the opposite.

But on two days of the year the Sun is exactly over Earth's equator giving equal light to both hemispheres; the vernal--or spring--equinox and the autumnal equinox.

However that whole "equal day" thing only applies if you live on the equator. For us good folks here at 40 degrees north of the equator that day is not equal to our night. In fact the only time we come close to equal day and night (12 hours each) is on March 17 and 18 when daylight is 11 hours and 58 minutes and 12 hours and one minute long respectively.

So, you see, location is important.

Now, about those new constellations.

Go outside about an hour after local sunset (consult your own sunrise-sunset calendar) and look south where you will find our old friend, the King of Winter, Orion, the Hunter slightly west of the meridian (the north/south line that divides the sky into east and west).

Orion has occupied the position of highest in the sky due south for the last month, and now he is moving off the scene stage left to return next autumn.

Now, turn to your left and look toward the eastern horizon for another of our old friends, Leo, the Lion, the quintessential spring constellation with the backward question mark for his head and mane and a triangle of stars for the hindquarters.

The bright star at the bottom of the question mark (or sickle) is blue-white Regulus or "Little King." There is another bright object in the area so don't confuse the two. Just above Regulus is the planet Jupiter.

At present, Jupiter is moving in retrograde motion--or westward against the background stars. In May it will return to regular motion--eastward--against the background. We will want to start a Jupiter watch now to follow it each night as it returns to a location near Regulus.

You will want to mark your calendars for the evening of June 30, when Jupiter and Venus execute a very close--less than one degree--conjunction. Also, on June 20, a slender crescent moon will fly past the pair.

SKYWATCH: New moon, Friday, March 20. That is also the day for a total solar eclipse, except if you're not a Polar Bear, or on the Faeroe Islands in the North Sea near the North Pole you won't see anything.

We will need to be content and wait for the April 4, total lunar eclipse. Tuesday, March 24, a five-day old moon visits Aldebaran in Taurus and the nearby Pleiades.

NEXT WEEK: More astronomical blathering.