Mercury -is not easily observable from the northern hemisphere this month.

Venus - climbs quickly into the pre-dawn eastern sky during September. It rises about 1.5 hours before the Sun early in the month and 3.5 hours before sunrise by the end of September. Venus waxes from a thin, 7% illuminated crescent to a gibbous shape that is 32% lit by month's end. However, since it is now pulling away from the Earth, Venus shrinks in angular size from 53 to 34 arc seconds.

Mars - rises before midnight and transits at dawn for northern observers. It brightens to zero magnitude on September 25 and attains a diameter of close to ten arc seconds during the course of the month. Mars passes less than one degree north of M1 (the Crab Nebula) on the mornings of September 16 and 17. As it glides between the horns of Taurus, Mars reaches western quadrature and becomes distinctly gibbous on September 17. On September 25, Mars is as close to the Earth as it is to the Sun. The Red Planet enters the constellation of Gemini on September 29.

Jupiter - sets in the west-southwestern sky by 1:00 a.m. EST. A shadow transit of the planet by the Galilean satellite Europa begins at 9:21 p.m. EST on September 2. A transit of Jupiter by Europa begins at 9:20 p.m. EST on September 8. Although dimming slightly, it is a brilliant object and a magnificent sight in a small telescope.

For detailed postions of Jupiter's Moons try this interactive javascript utility.

Saturn - is visible once again in the morning sky. The Ringed Planet is 0.8 degree north of Regulus on September 1. By September 30, it rises just after 4:30 a.m. EST. On that night, Saturn is 3.5 degrees to the east of Regulus and Venus is almost 7 degrees to its west.

The Cassini spacecraft continues its observation of Saturn and its many moons and rings. For the latest images from Cassini, see:

http://saturn.jpl.nasa.gov/home/index.cfm

For detailed postions of Saturn's Moons try this interactive javascript utility.

Uranus - reaches opposition on September 9. The planet that Sir William Herschel discovered in 1781 is visible for the entire night and can be seen without optical aid from a dark site. Uranus is within one degree of Phi Aquarii (magnitude 4.2) for most of the month. On September 1, it is just 0.3 degree northwest of Phi. By September 8, Uranus has moved to 0.5 degree west of the star.

A finder chart for Uranus can be found on page 66 of the May issue of Sky & Telescope.

Neptune - is 2.5 degrees northeast of Iota Capricorni (magnitude 4.2) in northeastern Capricornus on September 1. The eighth planet continues its slow westward motion and culminates around midnight.

A finder chart for Neptune can be found on page 66 of the May issue of Sky & Telescope.

Pluto - is located in northwestern Sagittarius approximately 8.8 degrees west of M17 (the Swan Nebula) and 16 degrees northeast of Jupiter.

Eris (pronounced "EE-ris") - formerly known as Xena, 2003 UB313, and "the tenth planet" - is magnitude 19 in central Cetus, high in the south during evening.

For detailed information please visit Astronomical Delights

Asteroid 2 Pallas - On the night of September 1, asteroid 2 Pallas (magnitude 8.8) passes 0.2 degree east of 34 Pegasi (magnitude 5.8). The next night it passes 0.2 degree to the south of the star. The second largest minor planet (570x525x482 kilometers) travels southwestward through Pegasus and into Aquarius this month.

Alpha Aurigids meteor shower - a normally minor meteor shower which is associated with the long-term periodic comet C/1911 N1 (Keiss) and whose radiant is near the first magnitude star Capella, may produce a meteor outburst that peaks at 7:36 a.m. EST on the morning of September 1. Observers in western North America and Hawaii are favored. Unfortunately, the shower is compromised by a 76% illuminated gibbous Moon.