Bright planets herald the autumnal equinox on Sept. 22

Glenn K.
Glenn K. Roberts
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As the September twilight falls about 45 minutes or so after sunset, Mars and Saturn appear in the WSW sky.

Both planets begin the month about 10 degrees (approximate width of your hand at arm’s length) above the horizon, with reddish Mars to the left and golden Saturn to the right.

By the end of the month, Saturn will disappear into the glow of the sun and be lost from sight, while Mars will set about two hours after sunset for the remainder of the year. Look for Mars just to the right of the waxing, crescent moon on the evening of Sept. 19.

Jupiter makes its appearance in the eastern night sky around midnight in early September and by 10 p.m. by months end. Always a spectacular sight in any decent-sized telescope, Jupiter grows both in size and brightness this month. The last quarter moon hangs just below Jupiter in the pre-dawn sky on Sept. 8.

Venus graces the pre-dawn sky as the morning star this month, rising in the east about three and a half hours before the sun. On Sept. 12, about an hour before sunrise, look for this brilliant planet sitting about one third of the way up the eastern sky to the left of the crescent moon.

On the last morning of the month, Venus will sit just to the upper right of the bright star Regulus in the constellation of Leo - the Lion. Watch for Venus and Regulus in a very close conjunction on Oct. 3.

The last two weeks of September bring an opportunity to view one of the heaven’s unique sights — the Zodiacal Light. Best seen from a dark location, the Zodiacal Light appears as a tall, broad, rightward-leaning pyramid of light rising up from the eastern horizon about two hours before sunrise. Venus will appear almost exactly on its axis. The Zodiacal Light is sunlight reflecting off myriad dust particles from comets scattered within the inner part of the solar system.

From a dark site and under clear viewing conditions, the Zodiacal Light can be quite spectacular and is always worth looking for.

Though no major meteor showers occur in September, the autumn months usually bring a higher number of sporadic meteors emanating from numerous directions. Don’t be surprised if, when out looking at the planets or the Zodiacal Light, you see any number of bright meteors randomly streaking across the night sky.

The autumnal equinox (the official beginning of autumn for the northern hemisphere) occurs at 11:49 a.m. on Sept. 22. This is the second of two times each year (the other being the vernal equinox in March) when day and night are equal in length. After Sept. 22, the nights will gradually get longer as we slowly move towards winter.

Type in equinoxes on Google for more information.

This month’s full moon is known as the harvest moon (the full moon closest to the autumnal equinox), as this is the time of year when farmers use the bright moonlight to extend the hours by which they can harvest their crops.

Until next month, clear skies and good hunting.


Events (ADT)

Sept.  8 - Last quarter moon; 10:16 a.m.;

Sept. 15 - New moon; 11:10 p.m.;

Sept. 22 - First quarter moon; 4:42 p.m.;

Sept. 30 - Full (harvest) moon; 12:18 a.m.


Glenn K. Roberts is a member of the Charlottetown Centre of the Royal Astronomical Society of Canada (RASC). His column appears in The Guardian once a month. He welcomes comments from readers. Anyone who would like to comment on his column is encouraged to email him at

Organizations: Royal Astronomical Society of Canada, Google, Charlottetown Centre

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