What's Up in August 2022

GARDEN ROUTE NEWS - The month starts with a thin waxing crescent Moon that becomes full on the 12th.

It will be a slightly larger than normal full Moon as it will be at perigee (closest to Earth) - on this occasion 356 379km away. Not quite a super Moon, but in reality it is difficult to see that this full Moon is larger than normal; the increase in size is only a few percent.

However, once again the Moon can be used as a marker for finding the planets, with the exception of Mercury. They are only visible before sunrise.

As I have said before, away from the city/town lights the Milky Way stretches from north-east to south-west across our night sky.

The inconspicuous constellation Vela is low at the south-west end and above this is the "landmark" of the southern skies: the Southern Cross and the Pointers, Alpha and Beta Centauri, that dominate the evening sky.

Even though the two pointers appear to be about the same brightness, Alpha Centauri is the nearest naked-eye star to the Sun, about 4,26 light years away. Beta Centauri is 120 times further away and about 15 000 brighter!

The distance to Alpha Centauri was first measured by Henderson, an astronomer at the then Royal Observatory (now South African Astronomical Observatory) here in the Cape in 1832.

However, he didn't publish, and in 1836 the measuring of the distance to a star was accredited to Bessel in Germany - the punishment for not publishing! Alpha Centauri itself is actually a multiple-star system, its two main components orbiting each other every 81 years, and with a small telescope the "star" will appear to be a double.

There is a third component, however - Proxima Centauri, not visible to the naked eye but the closest star to the Sun.

At the other end of the Milky Way is the constellation of Cygnus, which is often referred to as the Northern Cross. To the left (west) of this, the bright star Vega in the constellation of Lyra is visible.

Above Cygnus in the Milky Way is the bright star Altair in the constellation of Aquila. Other bright stars are Spica in the west, Archernar in the south-east and Arcturus in the constellation of Bootes in the north-west.

Antares, the heart of the Scorpion, is almost overhead and shines brightly, its reddish colour making it easily recognisable.

The morning sky now has isiLimela (Pleiades) well up in the north-east together with the small open cluster of the Hyades, with red star Aldebaran prominent slightly to the right of the A-shaped cluster.

Orion is also visible and it is interesting to note how far it moves up in the morning sky each month. According to myth, because of the legendary rivalry between Orion and the Scorpion, the gods placed them at opposite ends of the night sky.

So as the Scorpion sets in the west at about 05:00, Orion the Hunter rises in the east.

Venus still shines brightly, low in the east just before sunrise. Above this, the other planets are visible close to the Moon: Saturn on the 12th, Jupiter on the 15th and Mars on the 19th.

The Southern Ring Nebula, catalogued as NGC 3132, is a planetary nebula, the death shroud of a dying sun-like star some 2 500 light years from Earth. Composed of gas and dust, the stunning cosmic landscape is nearly half a light-year in diameter, explored in unprecedented detail by the James Webb Space Telescope. In this NIRCam image the bright star near the centre is a companion of the dying star.