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Star Trak: September 2019

For immediate release: August 30, 2019

BLOOMINGTON, Ind. -- The two giant planets, Jupiter and Saturn, will highlight the evening sky in September.

As the month begins, Jupiter will be 25 degrees high in the south-southwest an hour after sunset. By month's end it will appear 20 degrees high in the southwest. The planet will be 20 times brighter than Antares, the bright red-orange star 8 degrees to Jupiter's lower right (west). To observe Jupiter with a telescope, start in late twilight before it sinks too close to the horizon. It will set after 11 p.m. local daylight time at the start of the month and about two hours earlier at the end. Any telescope will show Jupiter's four bright moons, first seen by Galileo.

About 30 degrees east of Jupiter, bright yellow Saturn will be at its highest point in the south as darkness falls at the beginning of September, and it will continue to be a fine sight past midnight. Its rings will be tilted 25 degrees to our line of sight. Saturn's brightest moon, Titan, will show up in any telescope. Titan will be due south of the planet on Sept. 7 and 23 and due north of it on Sept. 16.

Venus and Mercury will be barely visible low in the west in bright evening twilight as the month ends. Venus will be 1 degree above the western horizon 30 minutes after sunset on Sept. 30, showing up only because it shines so brightly. One binocular field to the upper left (south) of Venus will be much fainter Mercury.

Mars will be too close to the sun to be seen during September. It will become visible again in late October.

Zodiacal light

The Milky WayThe Milky Way
Photo Credit: NASA

If you live in an area dark enough for you to see the Milky Way sprawling across the night sky, you have a chance of seeing the interplanetary dust in the plane of our solar system. Moonless autumn mornings are a good time to see this dust. Shortly before twilight begins, look for a faint cone of light spreading upward from the eastern horizon over a large area of the sky. This "false dawn" is the zodiacal light, which is sunlight reflected from trillions of dust particles left behind in space by comets and asteroids that orbit the sun in the same plane as the planets.


The sun will arrive at the September equinox Sept. 23 at 3:50 a.m. EDT, marking the start of autumn in the Northern Hemisphere and spring in the Southern Hemisphere. For the next six months in the Northern Hemisphere, the nights will be longer than the days.

Moon phases

The moon will be at first quarter on Sept. 5, full on Sept. 14, at third quarter on Sept. 21 and new on Sept. 28.

Author: Hal Kibbey Email: hkibbey [at]

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