A time of year when the days get rapidly longer
THE MONTH starts with a waxing gibbous moon that becomes full on the 4th, with new moon following about two weeks later on the 18th.
The actual time of the new Moon is 8.46pm so the first crescent will not become visible till the evening of the 19th, with the sighting marking the start of Eid.
On the 22nd is the spring equinox, Latin for “equal night” – the time when the length of the day is the same as the length of the night.
One might expect that the length of day and night should be equally 12 hours. Instead, daylight lasts for an extra eight minutes due to the size of the sun and the bending of light (refraction): the actual 12-hour day occurred on the 19th.
Some regard this as the beginning of spring, while others say September 1 marks the beginning of spring. I won’t enter this debate, but it is the time of the year when the days are getting longer most rapidly in the souther n hemisphere. Careful observers will also notice that the Sun rises to the south of east and sets to the south of west from now on.
However this equinox does mark the end of the southern winter half of the year, lasting 186.4 days and the start of the northern winter-half of the year, lasting 178.8 days. The colder half of the year lasts about seven-and-a-half days longer for us because the Earth’s orbit is not circular (but elliptical, slightly egg-shaped) and the Earth travels more slowly at this part of its orbit.
Mercury is visible just after sunset until the 20th when it sets with the Sun, after which it becomes a morning object, rising early in the dawn sky.
Jupiter is well up in the evening sky and sets as the sun rises. The other planets are morning objects: Venus unmistakably bright in the east, with Mars visible much earlier and Saturn rising a little before dawn.
The evening sky to the west shows the Scorpion heading for the horizon, with the red supergiant star, Antares, at its heart and set- ting around midnight.
To the left (south) of Scorpious, the Southern Cross and the Pointers earn their name of Thutlwa, or the “Giraffe Stars”, as they graze the tops of the trees: the wellknown group of stars is low above the horizon.
To the north, the bright star Vega is unmistakable low above the horizon, to the right (east) of which is Deneb, the brightest star in the constellation of Cygnus, the Swan. On a par with Rigel, it is one of the great stars: 25 times bigger than the Sun, 60 000 times more luminous and about 1 500 light years away.
The morning sky is truly spectacular, and early risers can enjoy some beautiful sights. Orion is now well up, with isiLimela and the Hyades to the left. Sirius shines very brightly further left and forms an equilateral triangle with Betelgeuse (red supergiant) and Procyon, the Little Dog Star.
Castor and Pollux can be seen low in the north-east. On the morning of the 10th, a waning gibbous Moon can be seen close to Limela and by the following morning it will have passed by.
For midnight owls there is a minor feast. At 1am or later, Orion can be seen rising along with Aldebaran, the red giant star on the small cluster of the Hyades to the left. Limela is further left, and low in the north-east, our twin galaxy, Andromeda, can be seen. It is the remotest object visible to the naked eye, 2.3 million light years away, and a pair of binoculars will reveal its shape clearly.