The night sky in May

If you have never watched the sky at night, don`t miss out on the splendid alignment of the planets today! (see this month`s view of the sky). May is the last month during which we can see the brightest star in the sky in the early evening hours. This is not the north star Polaris, as many think, but the star Sirius. It can be seen looking low towards the southwest. The name Sirius is derived from Greek and means `scorching`.

The Egyptians called it after their god Osirus; the Arabs know it as Al Shira. Sirius is also known as the Dog Star from the constellation in which it lies, Canis Major (the Great Dog). Light from this star takes nearly nine years to arrive to the Earth. This makes it one of the nearest stars to the Sun. Sirius is actually a system of two stars in orbit around each other. Almost all the light comes from the primary star, Sirius A, which is a normal star about 2.3 times bigger than the Sun and white in colour. Its faint companion, Sirius B, was discovered visually in 1862, and is a small white dwarf star. It gives out only one ten-thousandth the light of Sirius A! The pair take 50 years to complete one orbit.

May activities

An observation for the public will be held starting 6 p.m., next Saturday 11 th May, at City Gate, Valletta. Telescopes and special filters will be available during this observation of the Sun. Afterwards, the Moon and planets Jupiter, Saturn, Mars, Venus and Mercury will also be on view. More information at www.maltastro.org.