Mercury makes a brief appearance low on the pre-dawn eastern horizon at month’s end but will likely prove too dim to see in the brightening sky.

Venus rises well before sunrise on the eastern horizon as June opens. Make an effort to look for Venus about an hour before sunrise on the morning of the 17th when a waning crescent moon is directly to its right.

Mars is at its biggest and brightest since 1988 during June. It rises on the southeast horizon about an hour after sunset as June opens but will be visible at sunset by midmonth. June 21st marks both Mars’ opposition, placing it in a line with the earth on the same side of the sun, and the planet’s autumnal equinox, a fact that gives a panoramic view of the Red Planet from the equator to both poles.

Jupiter is at conjunction in June, placing it on the opposite side of the sun from Earth and, as a consequence, is lost to view for most of the month. Look for Jupiter to make a brief appearance low in the east just before sunrise at month’s end.

Saturn emerges from behind the sun at midmonth to appear low in the northeast about an hour before sunrise. On the 19th, Saturn is to the lower left of the thin crescent moon.

Uranus and Neptune rise around midnight high in the southeast among the stars of Capricornus. A finder chart and telescope will be needed to spot these far distant planets.

Pluto, like Mars, is also at opposition this month but 3 million times dimmer! It will require at least a 10-inch telescope to find Pluto’s dim speck among surrounding stars.

Our Celestial Neighborhood

Over the next few months, our closest celestial neighbors, the other planets of the solar system, will be highlighted in turn. Mercury, the innermost planet, is only about 36 million miles from the sun. It is a small planet at 3,024 miles in diameter, making it only 40 percent larger than our moon. Its year, the time needed for one orbit of the sun, is 88 Earth days while its day, or period of one rotation, is 59 Earth days.

The surface of Mercury appears featureless in telescopes and it was believed until 1965 that it had a synchronous orbit just like the moon, i.e. its periods of orbit and rotation were the same, and that it always presented the same face to Earth observers.

The Mariner 10 flyby in 1974 revealed that Mercury has a barren, pockmarked surface like the moon with one huge impact crater measuring 800 miles in diameter. The long “day” gives wild temperature fluctuations on the night and day sides of the planet ranging from -279 to 806 degrees F. Today, scientists are trying to verify a belief that water exists in the subsurface of the darkened regions of the poles.

June Events

1 Sunrise, 4:53 a.m.; sunset, 8:14 p.m. The bright star below the moon tonight is blue-white Spica.

3 Whitsun commemorating Pentecost and is the 7th Sunday after Easter.

5 Full moon, 9:40 p.m. The full moon of June is known as the Rose Moon, Honey Moon, or Strawberry Moon.

6 Look for Mars just to the right of the moon during the early evening hours.

11 The moon is at apogee, or its most distant point from the Earth, today.

14 This is the date of earliest sunrise while latest sunset falls on June 27. Moon in last quarter, 11:29 p.m.

17 Look for the thin crescent moon to the right of Venus in the pre-dawn sky.

19 The moon is to the upper right of Saturn about an hour before dawn. Venus is well to the upper right of both.

21 Summer solstice, 3:35 a.m. This marks the sun’s northernmost point in its journey above the equator. New moon, 7:58 a.m. The sun enters Gemini on the ecliptic but astrologically is entering the sign of Cancer.

23 The moon is at perigee, or closest approach to the earth, today.

28 Moon in first quarter, 11:20 p.m.

30 Sunrise, 4:52 a.m.; sunset, 8:25 p.m.