May brings with it the first frosty nights of winter, as well as the return of the magnificent winter Milky Way, which will straddle our nights until the return of spring. Look out for the Milky Way low in the east, near the bright star Antares, once the nights are fully dark. Streetlights interfere with the view, as does the Moon.
Bright stars for May include white Sirius and Procyon low in the west after sunset, blue-white Canopus in the south-west, blue-white Spica close to the planet Mars towards the north, orange Arcturus low in the north-east, red Antares in the east, and yellow Alpha Centauri towards the south-east. Saturn is in between Spica and Antares. Can you spot the Southern Cross high in the south, close to Alpha Centauri?
The stars are different colours because they all have different surface temperatures. The hottest glow blue-white, moving through white, yellow, orange and eventually red as the surface temperature cools. The reason the Sun is yellow is simply due to it having a surface temperature of 5,800 degrees. If it was hotter, it would be white. Imagine what a day would look like if the Sun was white!
Through a telescope Mars is currently showing lots of dark surface markings as well as the North Polar Cap. Amazingly, a small telescope reveals clouds on Mars, and even fog and frost on the surface of the Red Planet. Now is an excellent opportunity to see Mars for yourself before it receeds away from us in a couple of months time.
Jupiter is visible as a bright yellowish ‘star’ low in the west after sunset in the constellation Gemini. Jupiter wil pass behind the Sun as seen from Earth in July, before re-appearing in the early morning skies during next spring. A pair of binoculars reveals Jupiter’s four large Moons, as well as ever-changing details on the giant planet’s cloud tops.
The highlight for May is the planet Saturn, which reaches ‘opposition’ (the point where is lies exactly opposite the Sun in our skies, hence is visible all night) on the 10 May. Saturn can be seen shining as a fairly bright yellowish ‘star’ low in the east after sunset in the constellation Libra. The map accompanying this article will help in identifying it.
Through a telescope Saturn is a magnificent sight. The planet’s giant system of rings is clearly seen, as well as several of its Moons and hazy cloud markings on the planet itself.
Also accompanying the article this month is a colour image of Saturn taken by the author on 17 April from his back garden in Bungendore.
The image (taken with a 5-inch telescope) captures the details that small telescopes reveal, including the rings, a 4,700km gap in the rings called the ‘Cassini Division’ (named after a 16 Century Italian Astronomer who was the first to see it), the shadow that the planet casts onto the rings (top right of the planet) as well as the yellowish-brown cloud features of the planet itself.
Saturn is easy to see in our evening skies, take this opportunity to see it for yourself!