The September 2018 Night Sky

Welcome to the September night sky. This is the month of the Autumn equinox in the northern hemisphere, when the Sun crosses the celestial equator heading south. It will mean that the entire world will have approximately 12 hours of darkness and 12 hours of daylight.

The Sun has been in the news lately because of the launch of NASA’s historic mission, the Parker Solar Probe, on August 12. This probe is on its way to Venus and when it passes close to the planet on October, around the 3rd, it will use this planet’s gravity to change its orbit to enable it to swing by the Sun on November 5.

The Parker Solar Probe is expected to make 24 close passes to the surface of the Sun where its heat shield will experience temperatures of over 1000ºC. The Parker Probe will be 50 times closer to the Sun than the Earth and will be traveling at speeds of up to 690,000kph making it, by far, the fastest man-made object.

The Parker Solar Probe is named after Eugene Parker, a solar physicist from the University of Chicago, who studied the Sun extensively to discover just how complex solar activity really is with multiple interactions with high temperature plasma and powerful magnetic fields.

The fact is that the Sun is not well understood in detail and its short-term variations have an immediate effect on Earth and other worlds. For example, in 1859, a solar coronal mass ejection upset all the electrical circuits on the Earth and if it was to happen today, the effects would be catastrophic.

The brilliant planet Venus can still be seen low on the southwestern horizon just after sunset and, on September 12, the thin crescent Moon will be seen just above this planet. A day later, on the 13th, the Moon will be close to Jupiter, and on the 17th the first quarter Moon will be close to Saturn.

There are two notable meteor showers in September, the Epsilon Perseids on the 7th and the Alpha Aurigids on the 23rd. The first is easy to see as the Moon is out of the night sky at that time and the radiant point is above the horizon all night. The second shower has been known to produce fast and bright meteors, but the Moon will be near full on that night.

The Moon is at last quarter on the 3rd, new on the 9th, first quarter on the 16th and full on September 25.

By Clive Jackson
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Clive Jackson is the Director of the Camera Obscura (next to the Castle in Tavira), specialising in education and public outreach.
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To see the September Sky Map click on the pdf link below