August 2001

By Steve Stefanik

Although the planet Mars still dominates the southern summer sky in the early evening, August will be the last month to get a good look at it. Currently it is shining at magnitude –1.4 east of the bright red star Antares in the constellation Scorpio the scorpion and it is still 17 arc seconds in angular size but it will diminish in brightness to –0.8 and 13 arc seconds across by the end of the month. You’ll only have about 2 hours to observe it each evening before it gets too low above the southwestern horizon. It sets by midnight.

About the time Mars is setting, the planets Neptune and Uranus are high in the southeastern sky among the stars of the constellation Capricorn the sea goat. Neptune reached opposition on July 30 and is as bright as it gets at +7.8 magnitude being directly opposite the sun from us but you’ll need at least binoculars to locate it. Uranus on the other hand won’t reach opposition until the 15^th of this month but when it does it will shine at magnitude +5.7 and you may spot it with your unaided eyes under dark viewing conditions away from city lights.

A spectacular conjunction of the planets Jupiter and Venus will take place tomorrow morning in the east before the sun rises. Both planets are located in the constellation Gemini the twins and will be within 1.25 degrees of each other. Venus is the brighter of the two at –4.5 magnitude but Jupiter becomes the second brightest planet at –2.0 magnitude taking that distinction away from Mars. In the days following after the conjunction, Jupiter will climb up and away from Venus by 1 degree per day, which is on its way down. The pair will be separated by 5 degrees on the 11^th and 25 degrees by the end of the month.

Higher and to the right of these brilliant planets, the relatively dim +0.2 magnitude planet Saturn hangs between the open star clusters Pleiades and Hyades in the constellation Taurus the bull.

The planet Mercury is in superior conjunction with the sun today and will be all but impossible to spot in the glare of the sun low on the western horizon this month.

August also hosts the annual Perseid meteor shower. Every year at this time the earth passes through the path of comet Swift-Tuttle. The debris left in its wake enters our atmosphere and burns up producing a shower of "shooting stars". Although you might see Perseid meteors on any August night, if you look toward the constellation Perseus in the northeast after midnight on the 12^th you may see as many a 60 meteors per hour when they are expected to peak.