Starwatch: Goodbye, harvest moon, it’s time to visit the twins | Astronomy

Bid farewell to the harvest moon this week as it cruises through Gemini, the twins, for a close encounter with the star Pollux.

In the early hours of 20 September, the moon will be a beautiful waning crescent with 30% of its visible surface illuminated. As the week goes on, and the moon draws closer to the sun, the illuminated percentage will drop and the moon will rise later and later until it disappears into the morning twilight. It will then be reborn a few days later in the evening sky as a new moon.

The chart shows the view looking north-east at 01.00 BST on 20 September, when the moon will be close to Pollux, one of the twins in Gemini. The further west you are located, the closer the conjunction will appear to be.

According to Greek mythology, Pollux and his twin half-brother, Castor, were Argonauts, who sailed with Jason on his quest to retrieve the golden fleece. In traditional Chinese astronomy, these stars belong to the North River “mansion”“, the equivalent of a western zodiacal constellation. The pairing is visible from the southern hemisphere in the pre-dawn hours in the north-north-eastern sky.