September 1997

by Steve Stefanik

A six day old waxing crescent moon, Spica the brightest star in the constellation Virgo, the brilliant -4.0 magnitude planet Venus and the not so brilliant +1.0 planet Mars hover over the southwestern horizon as the sun sets tonight.

The familiar summertime stars Arcturus and Antares in the constellations Bootes and Scorpius are noticeably lower in the western sky. The "Summer Triangle" composed of the three stars Vega, Altair, and Deneb in the constellations Lyra, Aquilla, and Cygnus are directly overhead as darkness envelops us earlier now. The constellations Pegasus and Pisces are beginning to rise earlier in the evening. All these are signs that Fall is not far behind. The autumnal equinox occurs on the 22nd when the sun crosses the ecliptic at 2:50 p.m. rising due east and setting due west on that day. From that day the sun will begin rising a few minutes later each morning and earlier each evening until we reach the winter solstice in December.

Venus remains relatively high in the southwestern sky until twilight. By then the planet Jupiter is relatively high in the southeastern sky as it takes over the role as the brightest star-like object in the sky except for the moon of course. The giant planet is easy to spot even with just your eyes. Look for the bright -2.7 magnitude planet among the stars of the constellation Capricorn. A fairly bright 4th magnitude star will appear next to it tonight. A waxing gibbous moon will be above it on the night of the 13th.

The planets Uranus and Neptune are in the nearby constellation Sagittarius. Magnitude +7.9 Neptune is virtually impossible to see without a telescope but +5.7 magnitude Uranus can be made out as a 6th magnitude greenish blue star just to the west of Jupiter.

By midevening the ringed planet Saturn rises in the east among the dim stars of Pisces below the "Great Square" of Pegasus. At magnitude +3.0 its the brightest star-like object in that region of the sky. It’s rings can be seen through a telescope, tipped 27 degrees toward the south making the dark divisions between them more visible than they were last year since their edge-on view in 1995.

The last planet to make its appearance is Mercury. Look for this speedster low in the southeast before sunrise just below Regulus the brightest star in the constellation Leo. This will be its best morning apparition of the year.