On the 11th, the third-quarter Luna skirts less than half a degree south of the cluster, M35, in the eastern morning sky for early risers. On the morning of the 13th, Venus is 4 degrees south of the Moon. By September 25, Jupiter is 1.4 degrees north of the first-quarter Moon, while a little later, Saturn is 3 degrees north. Jupiter and Saturn are gradually closing up the gap that will culminate on a closest approach on December 21. Neptune and Uranus are visited by the Moon on the 2nd and 7th, respectively, see below.
Mercury gradually moves away from the Sun in what will be its greatest elongation east (GEE) in the western evening sky. Unfortunately, the angle of the ecliptic makes this an unfavourable apparition for northern observers, so Mercury hugs the horizon right at sundown – a tough observation. On the early morning of the 21st, the speedy planet is 0.3 degrees above the bright star, Spica, in the constellation Virgo (The Maiden).
Venus commands the morning sky well above the horizon, shining like a beacon before sunrise and often described as a UFO by the unknowing! The waning crescent Moon passes by on the 13th.
Mars is in its best apparition of the 2020s, rising at sunset and setting at dawn. The Moon joins up with the Red Planet on the evenings of the 5th and 6th, an occultation in South America. Mars appears to become stationary on the 9th and thereafter begins retrograde motion – apparently moving westward. This strange behaviour greatly puzzled the ancient astronomers, resulting in all sorts of weird ideas. What they failed to take into account was the Earth’s own motion, more rapid than Mars, so we overtake it during an opposition. It was Copernicus and Galileo who put forth the idea that the Sun, not the Earth, was at the centre of the Solar System.
Jupiter has been retrograding and becomes stationary on the 13th beginning prograde motion against the background stars of Sagittarius. Watch for the Moon passing by on the 25th.
Saturn has also been retrograding, and begins prograde motion on the 29th. The Moon catches up with the Ringed Planet on the 25th, only 2 degrees south.
Uranus rises before midnight. On the night of September 7, the Moon is directly south of the blue-green gas planet with the Pleiades and Hyades clusters off to the east.
Neptune rises about 8 p.m., and the Moon joins up on the evening of the 2nd.
The Autumn equinox occurs on September 22 at 1:31 UT (early in the morning in North America).
The zodiacal light is visible in the east before sunrise for the last two weeks of the month.
James Edgar has had an interest in the night sky all his life. He joined The Royal Astronomical Society of Canada in 2000, was National President for two terms, is now the Editor of the renowned Observer’s Handbook, and Production Manager of the bi-monthly RASC Journal. The IAU named asteroid 1995 XC5 “(22421) Jamesedgar” in his honour.
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