Northern Hemisphere gazer's guide
All month: Both evening- and morning-planet watchers will have a field day this month, with Saturn, Mars, and Jupiter in the sky virtually all night long. Venus and Mercury, unfortunately, are out of the picture: Both are close to the sun all month.
Saturn, Mars, and Jupiter put on a great show. In early evening, they are up in the east, bright Jupiter lowest, Mars and Saturn above to the right, quite close to each other. Two bright stars are also nearby: Antares, in Scorpius and reddish in appearance, between Jupiter and Mars, andSpica, above and to the right of Saturn and Mars. The whole squad of bright objects moves to the right (west) during the night because of Earth's rotation, but they keep their order and spacing (with minor changes). By midnight, they are high in the south, Jupiter to the left, Spica to the right, and by dawn they are in the west, Jupiter highest and the others curving down toward the horizon. Watch especially from the 8th until the 15th, when the moon is part of the scene.
Apart from their motions together during the night, some slight shifting of position takes place among them because of the planets' motions in orbit around the sun. At the beginning of June, all are sliding slowly to the right (west) relative to the stars (the planets' retrograde motion), and you should see Jupiter move up a bit on Antares. Mars and Saturn draw away from Antares toward Spica.
This jockeying around changes later in the month (the 20th), when Mars ends its retrograde motion and resumes its normal easterly drift through the stars. Despite this, it remains close to Saturn all month, closer than the two bright twin stars of Gemini. The end of Mars's retrograde path also signals its gradual disappearance from the evening sky. It is now moving almost directly away from Earth, dimming rapidly. But it will return again in summer 1986 to an even better and brighter opposition.
By the end of June, all the planets are evening sky, whereas all were morning stars earlier in the year. It will not be until September that we again find a planet above the horizon at sunrise!
The events described below occur in local time unless otherwise stated.
June 1: New moon was only two days ago, but you might see a very slender crescent in the west tonight during late twilight. The moon sets about two hours after the sun, in Gemini.
June 2: Tonight's three-day-old crescent moon is nearby in line with Pollux and Castor, the twin stars of Gemini. Look to the moon's right when the sky in the west grows dark enough to see stars.
June 4-5: The fat crescent moon is in Leo both nights, moving past Regulus, the Lion's brightest star, during the day on the 5th. Regulus is the bright star to the left of the moon on the night of the 4th, to the right on the 5th. The circle of stars above Regulus is Leo's head, and way above it, hanging at the top of the sky, you'll find the Big Dipper. Leo is always beneath its bowl.
June 6-7: First-quarter moon is at 11:42 a.m., Eastern standard time. It's moving from Leo into Virgo tonight setting at about 1 a.m. Perigee moon (nearest Earth) is early on the 7th.
June 8: The star beneath the gibbous moon is Spica, in Virgo. The other bright objects in the eastern sky are the planets Saturn, Mars, and Jupiter, the latter rising an hour or so after sundown.
June 9-10: The gibbous moon moves past Saturn and Mars during the day on the 10th, covering Saturn (an occultation) as it goes by over Southern and Southeast Asia. If you haven't met the two planets yet, the moon should make it easy on Saturday and Sunday night. They will be to the moon's left on the 9th, to its right and closer on the 10th. Saturn is the higher of the two, Mars the brighter. Both planets are still moving slowly to the right (west) near the border of Libra.
June 11-12: The reddish star below and to the left of the moon on Monday night is Antares in Scorpius. It's to the right of the moon on Tuesday night.
June 13: At full moon (9:02 a.m. EST, moving from Ophiuchus into Saggitarius) , a rather poor penumbral lunar eclipse takes place in the Far East. Tonight the moon is just to the right and a little above the ''teapot'' arrangement of stars in Sagittarius, but it will be a bit difficult to see them through the moon's glare.
June 14: Easy to find Jupiter tonight. It'sthe very bright object just above the moon. Watch closely for an hour or so and you will easily see the moon sliding slowly left relative to Jupiter. Actually, both are moving to the right because of Earth's rotation, but the moon is slower because of its easterly motion around Earth.
June 15: Venus is in line with and beyond the sun today (superior conjunction). After dawdling along for months as a poor morning star, it moves into the evening sky, but we won't see much of it until December. This one will not be a particularly good evening display for the planet.
June 16: When the moon comes up tonight (in waning gibbous phase) about 10 o'clock, see if you can find the five bright starlike objects stretched in line with it upward to the right (toward the south). In order they are Jupiter (brightest), Antares (reddish, in Scorpius), Mars and Saturn (very close to one another, Mars the brighter), and Spica (in Virgo). The six objects (moon, two stars, and three planets) line up through the zodiac from Capricornus to Virgo, tracing the approximate path of the Earth's orbit (the ecliptic) across the sky.
June 20: Mars ends its retrograde (westerly) motion and resumes its normal easterly path through the stars. The most noticeable effect will be a slow separation of Mars to the left from Saturn. Till now it has been moving closer. The brightness of Mars is also diminishing rapidly. By the end of June, Mars is only half as bright as it was in mid-May, but still more than double the brightness of Saturn. The moon is at apogee (farthest from Earth) tonight, close to the southern border of Pisces and Aquarius and just south of the vernal equinox.
June 21: The sun is at the summer solstice, the northernmost point on the ecliptic, in the constellation Gemini, one-fourth of the way around the sky east of the vernal equinox, just about where the moon is at the same time. Summer begins in the Northern Hemisphere at two minutes past midnight this morning. Although this is the longest day of the year, the earliest sunrise occurred about a week ago, and the latest sunset will be about a week from today. Last-quarter moon is about 6:10 a.m., EST.
June 23: Mercury, at superior conjunction, becomes an evening star.
June 26: Our last view of the late crescent moon during this cycle is probably this morning. Look in the east at dawn and you should see it. The bright star is to its left in Aldebaran, in Taurus.
June 28: New moon is at 10:18 p.m., EST, in Gemini.
June 29: Jupiter is the last of the eight planets to leave the morning sky. All winter, and again in April, all were morning stars. Now, with Jupiter at opposition from the sun today, all are evening stars.