September will be a special month because after several months with no planets in the evening sky, there will now be two. Early in the month, Saturn will be at its highest and brightest as Earth in its faster orbit passes it. Saturn will rise in the east as the Sun sets in the west, and it will be at its highest at midnight, straight south in the sky. This is a dim part of the sky, so Saturn will be easy to spot. With binoculars, it should appear to have an oval shape, and with a telescope, its rings will be visible. By the end of the month, Saturn will be well up by the time it gets dark, and it will set before dawn.

Venus will be the second planet, and it also will be unmistakable. It will be the only brilliant star-like object low in the western sky as it crawls slowly up and out of the twilight glow. It will be in the evening sky all winter. The other planets that will be in the sky are very bright Jupiter that will rise shortly before 1 a.m. as September begins and shortly before 11 p.m. at the end of the month. It will be followed by Mars about 45 minutes later as September begins, but its rapid eastward motion will cause Mars to rise about 2 hours after Jupiter by the end of the month.

Scorpius (the Scorpion) will still be prominent in the southern sky although it will have shifted noticeably westward and lower in the sky. It can still be used to help find the “teapot” of Sagittarius (the Archer) that follows closely behind and the twin stars of Libra (the Scales) that will be to its right (westward). The bright star Spica in Virgo (the Maiden) will be farther to the west, but it will be very low and almost gone for the year.

The line of three stars that form the scorpion’s head area also can be used to point upward to just west of the overhead to the bright star Vega in the tiny constellation Lyra (the Harp). Vega is the brightest of three bright stars in different constellations that make up the Summer Triangle. About two fist-widths at arm’s length to the southeast of Vega is Altair in the constellation Aquila (the Eagle). Deneb, which represents the tail of Cygnus (the Swan), will be about 2 fist-widths to the northeast of Vega. The swan’s large body extends almost through the Summer Triangle and ends in the fairly bright star Albireo that is revealed through a telescope to be one of the most beautiful double stars in the sky. The brighter stars of Cygnus also form the Northern Cross. The Summer Triangle has been in the eastern sky all summer, and now as autumn begins, it is high overhead.

Observing Highlights

*Sept. 5: The crescent Moon will be to the left of brilliant Venus low in the west during evening twilight.

*Sept. 6: The crescent Moon will be close to the left of the bright star Spica in the constellation Virgo (the Maiden). Venus will be farther to their right.

*Sept. 7: Saturn will reach opposition tonight when it will be opposite the Sun in the sky. It will rise at sunset, be at its highest at midnight (1:00 daylight time), and set as the Sun rises.

*Sept. 9: The Moon will be to the lower right of bright Antares and in the lower part of the three stars that make up the head area of Scorpius (the Scorpion). The Moon will move in its orbit and be to the left of Antares on the 10th.

*Sept. 14: Star Party sponsored by Grout Museum & Black Hawk Astronomy Club, Prairie Grove Park, Waterloo, 9-10:30 p.m.

*Sept. 16: The almost full Moon will be to the right or upper right of Saturn. It will be farther to the left of Saturn on the 17th.

*Sept. 22: Autumn will arrive in the northern hemisphere with the equinox when the Sun crosses the celestial equator, which is the projection of Earth’s equator on the sky. On this day the Sun will rise straight in the east and set straight in the west and everyone will have 12 hours of daylight (except at the north and south poles).

*Sept. 23: After they are in good view shortly after midnight and until dawn, the Moon will be to the upper right of Jupiter and farther to the upper left of Aldebaran in Taurus (the Bull).

*Sept. 25: After they rise at about 1 a.m., the Moon will be to the upper left of Mars.