Monday 16th to Sunday 22nd August 2021
Saturday 21st sees a Full Moon rising in the south east from around 9pm. To the left of the Moon will be planet Jupiter and to the right of the Moon, Saturn.
It's probably not the best time to dig out your telescope to view Saturn's rings as light pollution from the Full Moon will ruin the contrast of the rings. However, the following day Sunday 22nd it will be worth using your telescope to spot something unusual happening with Jupiter's Galilean moons.
On the Sunday, Jupiter will rise above the horizon just before the bright, almost-Full Moon. At that moment, just before 9pm, two of Jupiter's moons will be transiting the planet at the same time - both Europa and Ganymede will cast shadows on the planet's surface. Io will be slightly to the left of Jupiter, with Callisto much further away to the right.
Jupiter has 53 named moons and scientists have discovered a further 26 that are awaiting names. The four largest that I've just mentioned were first discovered by the Italian astronomer Galileo back in 1610 and made him realise that our Solar System is "helio-centric" with the Earth rotating daily and orbiting around the Sun.
His ideas contradicted scientific thinking of the time and he was tried by inquisition. Poor Galileo was found guilty of being "vehemently suspect of heresy". As a result, he was forced to withdraw his theory and spent the rest of his life under house arrest. Of course as the 17th Century progressed, other scientists proved that the helio-centric model was correct, but sadly too late for Galileo who passed away in 1642. Many consider him to be the "father of modern science".
Screenshots courtesy of Stellarium
Copyright Adrian Dening and Radio Ninesprings 2021