Equinoxes are opposite on either side of the equator, so the autumnal (fall) equinox in the Northern Hemisphere is the spring (vernal) equinox in the Southern Hemisphere and vice versa.
On the two equinoxes every year the Sun shines directly on the Equator and the length of day and night is nearly equal – but not exactly. The September equinox marks the moment the Sun crosses the celestial equator – the imaginary line in the sky above the Earth’s equator – from north to south and vice versa in March.
In the Northern Hemisphere, the fall equinox marks the first day of fall (autumn) in what we call astronomical seasons. There's also another, more common definition of when the seasons start, namely meteorological definitions, which are based on average temperatures rather that astronomical events.
read more
Sun halo spotted over eastern Singapore
The sun halo as seen from Simei at around 12.05pm on Sept 22,2020.ST PHOTO: BENJAMIN SEETOR
Many in eastern Singapore who looked skywards at close to noon on Tuesday (Sept 22) were treated to the sight of a large halo that ringed the sun.
The sun halo was spotted at locations such as Tampines, Simei and Ubi at around 12.05pm. Photos of the brilliant, multi-hued halo quickly made their way across messaging groups.
The optical phenomenon, which is not uncommon, typically occurs when there are thin clouds so high in the sky that they are made of ice crystals rather than water droplets.
read more
