Northern Sky: Mar 17 - 30

Northern Sky by Deane Morrison -  March 17-30 2018

March came in with a full moon, and it's going out with a full moon. Meanwhile, there's plenty going on in both the morning and evening skies.
 
Look to the south an hour before dawn and you'll see Jupiter blazing away. Then look eastward to see the stars of Scorpius, especially bright red Antares, the heart of the scorpion. Moving east again, we have the Teapot of Sagittarius. Right above the Teapot, Saturn seems to float motionless from day to day. But Mars is moving eastward against the background of stars, and it's rapidly closing in on Saturn. Mars stays to the west of Saturn until the end of March, but in the first week of April it's going to zip right below the ringed planet.
 
If you look above and east of Saturn and Mars, you'll see the Summer Triangle of bright stars high in the southeast. And off to the west of Jupiter, and higher, we have Arcturus, the brightest star in the northern hemisphere of sky. If you're ever in doubt as to which star is Arcturus, you can find it by extending the curve of the Big Dipper's handle.
 
In the evening sky, Venus is low in the west after sunset. So is Mercury, but not for long. The best night to see it was March 15. But now it's fading and dropping toward the sun because it's on its way between Earth and the sun. On the 17th Mercury is to the upper right of Venus, which is by far the brighter planet. On the 18th, a young crescent moon appears with the two planets--that will be lovely. But by the 21st Mercury will have dropped down to the level of Venus, and then it just plummets out of sight.
 
Sirius, the brightest star in the night sky, is still up. It's somewhat low in the south to southwest after nightfall. If you've never seen it, do take a look. And while you're at it, grab some binoculars and look for the Beehive star cluster, an inconspicuous little jewel that is now high in the south.
 
The Beehive is between two bright stars. One star is Pollux, the brighter of the Gemini twins. To find it, start with Sirius and look up to the bright star Procyon, and then up about the same distance again. The other star is Regulus, the brightest in Leo, the lion. It's east and a little south of Pollux. The Beehive is a bit dim, so you may need a star chart to get its exact location. But seeing it through binoculars is a real treat.
 
The spring equinox arrives at 11:15 a.m. on Tuesday, March 20. At that instant, Earth will be lighted from pole to pole and it won't be tilted with respect to the sun. That's because our spring equinox is an inflection point, the point at which the Earth’s orientation to the sun switches so that the Northern Hemisphere starts tilting toward the sun. The tilt changes fastest in the days closest to the equinoxes; therefore, these days we're gaining daylight at the maximum rate, approximately three minutes a day. Also, starting at the spring equinox, days get longer as you travel north.
 
March gets its second full moon on the 31st. This qualifies as another blue moon. The moment of fullness comes at 7:37 a.m. However, the moon sets over Grand Marais at 7:10 that morning. If you want to see the moon at its fullest, you might want to get outside by 6:30, or even earlier if there are obstructions to your view of the western horizon. Or just enjoy it the evening of the 30th.