The Sky In July And August

Natural History, July, 1999 by Joe Rao

MERCURY leaves the evening sky in July and arrives at inferior conjunction on July 26. It reaches its greatest elongation west of the Sun on August 14 and is visible very low in the east-northeast about forty-five minutes before sunrise from August 7 to 28, well above and to the left of Venus.

VENUS reaches its greatest brilliance on July 14 and makes an eye-catching conjunction with the crescent Moon the following evening. Leo's brightest star, bluish Regulus, will complete a compact triangle with this duo. Binoculars can reveal Venus's changing crescent (see "Venusian Testimony," June 1999). On August 20, Venus passes between Earth and the Sun and is lost in the Sun's glare. By August 28 it can be glimpsed again as it rises at dawn, very low in the east-northeast.

MARS moves away from the star Spica during July and into Libra from Virgo later that month. During July and August it is low in the southwest at dusk, setting at about midnight. By most standards it is quite bright, fading only slightly from zero magnitude by the end of August.

JUPITER rises at about midnight during July. It is high in the eastern sky by dawn. Look for it together with Saturn and the crescent Moon on the morning of July 8. In August the Moon passes Jupiter on the morning of the 4th.

SATURN rises at about midnight during July and just a few hours after sunset by August. It is well worth getting a look at Saturn with a telescope: the rings are tilted about 20 [degrees] from horizontal this month--the most since 1991. The Moon will be nearby on July 8 and August 5.

THE MOON in July is at last quarter on July 6 at 7:57 A.M. The new Moon is on July 12 at 10:24 P.M., first quarter comes on July 20 at 5:00 A.M., and full Moon is on July 28 at 7:25 A.M.

EARTH IS AT APHELION, its farthest point from the Sun (94,509,838 miles), at 7:00 P.M. on July 6.

A PARTIAL ECLIPSE of the Moon, visible only to those who live west of an imaginary line that runs from Nipigon, Ontario, to Southport, North Carolina, occurs on July 28 at sunset. The Moon enters the Earth's umbra at 6:22 A.M.

A TOTAL ECLIPSE of the Sun occurs on August 11. Although a primarily European spectacle, a partial eclipse at sunrise will be visible in the United States. The rising Sun will appear 85 percent eclipsed from Portland, Maine; 73 percent from Boston; 46 percent from New York; and just 14 percent from Washington, D.C.

THE MOON in August is at last quarter on August 4 at 1:27 P.M. The new Moon is on August 11 at 7:08 A.M., first quarter comes on August 18 at 9:47 P.M., and full Moon is on August 26 at 7:48 P.M.

THE PERSEID METEOR SHOWER will reach its peak on the night of August 12-13. Bright, swift streaks appear to emanate from the vicinity of the constellation Perseus. With no moonlight to interfere this year, an observer watching under a cloudless sky might count a hundred "shooting stars" per hour.

All times are in eastern daylight time.