June 1: Mercury and Mars are in conjunction about 1 p.m. Eastern standard time, and very close. By sundown tonight they will have separated a bit (mercury moving to the left, Venus to the right), but they will still be quite close. Using Venus as a guide (bright and easy to see low in the sky a little north of west), it should be easy to spot Mercury, just a little to the right of the much brighter Venus. If you miss it tonight, you might try again tomorrow night, or the next. Mercury will be a bit farther away each night (to the left and above Venus), but there isn't anything else nearby to confuse you. binoculars will help; put Venus in the center of the field, and the only other bright object in sight is Mercury. This is a very good opportunity to find the elusive little planet nearest to the sun. And it will be your last chance to see Venus as an evening star for a while. In a few more nights it will be gone, too low at sundown to see.
June 8: The moon is at perigee, the point in its orbit where it comes nearest Earth. Perigee tides are stronger than normal, but not as strong as the bimonthly spring tides that come with syzygy (when Earth, moon and sun are in line).
June 11: An occultation of the star Aldebaran by the moon occurs at about 7 p.m. EST, above the horizon in North America. But since it is daylight, observers will not be able to see the nearly moon cover the star.
June 14: Mercury, above the crescent moon tonight, is at its greatest distance to the left (east) of the sun, the position known as greatest easterly elongation. This places the planet in its most favorable position for viewing as an evening star. For the past two weeks, and for another, Mercury is high enough in the west-northwest to be visible briefly after sundown, but it dims appreciably during this time. By the 15th it is only half as bright as it was on the 1st.
June 15: Venus is in inferior conjunction, passing between Earth and sun. Moving form the sun's left to its right, the planet leaves the evening sky and becomes a morning star. The beautiful evening star we enjoyed for much of the winter and spring is gone, but in another week or so you will see venus again, rising in the twilight low in the east each morning.
June 17: The waxing crescent moon is very close to the star Regulus (in Leo) at dusk tonight. Jupiter, much brighter than Regulus, is to their left, and the moon moves between Regulus and Jupiter before they set. Two other planets, Mars and Saturn, are to the left of Jupiter, forming a line in the sky with jupiter and Regulus. The moon covers Regulus (on occultation) over western North America shortly after 4 p.m. EST, but unfortunatlely in daylight. Toward morning on the 18th (when they are below the North American horizon&gt; the moon also occults Jupiter over the Southern hemisphere.
June 21: The moon is at apogee, where it is farthest from Earth.
June 25: Mars has been creeping toward Saturn, and away from Jupiter, all month. Today it passes Saturn, moves to its left (east), then away from it, just about completing the disintegretion of the beautifulf configuration of planets and stars we saw in Leo all spring.
June 27: Mercury becomes stationary among the stars and begins its westerly (retrograde) motion toward inferior conjunction with the sun.
All month: For a few brief days this month, from the 11th (when Neptune is at opposition) until the 15th (when venus is at inferior conjunction), all of the planets are in the evening sky. Technically, this means that all are above the horizon at sunset, but it actually tells us little about whether they can be seen at night and where. But this time it happens that all five of the brighter planets, those that can be seen without a telescope, are conveniently gathered in the western sky at sundown, at least for the first week of June. The morning sky before dawn, in contrast, contains no planets to see.
Mercury and Venus put in their best show during the first few days of june, when Venus is still far enough to the sun's left to be seen after sundown. Mercury, going through a favorable evening elongation, is nearby the much brighter Venus, and you can nicely use Venus as a beacon to find it. Venus cannot be seen after the first week, but Mercury continues in favorable position until past mid- month, though it dims considerably.
Jupiter, Mars, and Saturn are well located in the southwest after dark, all still in Leo (to the left of its bright star Regulus), but not for long. Jupiter is the brightest object visible after Venus sets (except for the moon), and Regulus is to its right, Mars and Saturn to its left in that order until the 25th, when they change places. It will be especially interesting to watch the crescent moon move past these objects in leo from the 17th to the 19th.
Note that Venus (while it is visible), Regulus, Jupiter, Mars, and Saturn (and the moon when it is in the sky) lie very nearly along a line that curves upward from the west. Their locations very nearly approximate the ecliptic, the circle on the sky that traces out Earth's orbital plane.