May Sky Chart; Northern Hemisphere gazer's guide

May 3-4: The moon is at perigee (nearest earth) at midnight tonight, only one hour after it is new. The resulting perigee spring tide will produce exceptionally high tides during the day tomorrow and tomorrow night.

May 3-4: The Eta Aquarid shower of meteors, associated with Halley's Comet, radiates from the region of Aquarius just below the "head" of Pegasus, coming above the eastern horizon about 3 a.m., Eastern standard time. The shower reaches maximum about 9 a.m. EST on the 4th, but look from 2 a.m. on. It isn't the most productive shower (about 20 meteors per hour at its best), but the meteors are often swift, long, and bright. Well worth looking for, since the nearly new moon will leave the sky quite dark.

May 6-8: You should be able to pick up the young crescent moon on the evening of the 6th, certainly by the 7th. On the evening of the 8th, it will be below the "twin" stars of Gemini, Castor, and Pollux.

May 10-11: The first quarter moon is near Regulus, the bright star in Leo, on the night of the 10th. It passes the star during the day on the 11th, and appears to its left that evening.

May 13-14: The moon, now in its waxing gibbous phase, passes Jupiter and Saturn tonight, and it will surely help you find them if you haven't already. The two planets, Jupiter by far the brighter, will be the only bright objects you can see near the moon from dusk until they all set after midnight. The moon passes closest to Jupiter about 10 p.m. EST, closest to Saturn about 4 a.m. on the 14th. This motion between the two planets will be easy to follow.

May 15: The bright star near the moon tonight is Spica, in Virgo. Jupiter and Saturn are to their right (west).

May 17: The moon is at apogee, the position in its orbit where it is farthest from earth.

May 19: One day past full, the moon is near Antares, the brightest star in Scorpius, clearly red in color.

May 26: Mercury is at greatest easterly elongation, its greatest distance to the left (east) of the sun. This is often called its evening elongation, because the planet remains above the horizon as an evening star after the sun goes down, ordinarily placing Mercury in its best viewing position in the evening sky. Not all elongations are equally favorable for seeing Mercury, however. Much depends on the inclination of the planet's orbit to the viewer's horizon at the time. This elongation is reasonably good; the planet is still fairly high as the sun goes down, remaining above the horizon into the late twilight, when the western sky is dark enough to see it. From the 15th to the end of May, you can find the planet low in the west, below the stars Pollux and Castor. It will be easier to find Mercury from the 15th to the 20th or so, even though it is most distant from the sun on the 26th, because it is much brighter early in the period. By the 25th it will be dimming below the magnitude of the brighter stars because it is facing more of its dark side toward earth as it moves in between sun and earth.

May 28: Jupiter has been moving westerly (to the right) through the stars until now, its retrograde motion. This has been taking it slowly away from the nearby planet Saturn and from Virgo's brightest star, Spica, to their left. But its retrograde motion ends today. Jupiter becomes stationary momentarily, then resumes its normal easterly motion (to the left).

June 1: Another perigee moon occurs today, one day before the new moon. The effect of perigee will enhance tomorrow's spring tides.

All Month: Jupiter and Saturn are easily visible all month from dusk until they set after midnight. During the early evening, they will be high in the south in Virgo, very close to one another. The brighter one is Jupiter, brighter than any other object in the sky except when the moon is up. Saturn is just slightly to its left. Further left, the bright star is Spica, in Virgo. Watch carefully during May and June, and you will see Jupiter part slowly from Saturn while both move away from Spica.

The only other planet in good position this month (relatively speaking) is Mercury, going through a favorable evening elongation. From mid-May until early June it will be low in the west about three-quarters of an hour past sundown, looking very much like a very bright star below the twin stars of Gemini (Pollux and Castor). You may begin to see Venus, much brighter than Mercury but lower, in the last week of May, setting in the sunset glow. If so, look above it for Mercury.

Note in particular that the planets have just about deserted the morning sky this month, whereas only a few months ago they were quite prominent just before the dawn. The only planets above the horizon at sunrise are invisible, Mars because it rises too late. Uranus and Neptune too faint. And even Uranus leaves the morning sky on the 18th.

You've read  of  free articles. Subscribe to continue.
QR Code to May Sky Chart; Northern Hemisphere gazer's guide
Read this article in
QR Code to Subscription page
Start your subscription today