Welcome to the May night sky. This month, just after sunset over in the west, we get our last chance to see the gas giant planet Jupiter as it now sets soon after the sun.
Still over in the west but getting noticeably lower each evening is Venus. This planet is in the constellation of Taurus, but it’s in the part of its orbit that takes it closer to the Earth and, therefore, in a small telescope or good binoculars Venus will be seen to be getting bigger day-by-day and transforming into a thin crescent shape. In June, it actually passes in front of the Sun as seen from the Pacific area of our planet.
The planet Mars is at the moment in the constellation of Leo and is visible high up in the southwest soon after sunset. To the east of Mars, and practically due south during May evenings, the ringed planet Saturn can be seen in the constellation of Virgo.
Saturn is close to the white star Spica and although the two objects are of similar brightness, Saturn will have a slight yellow colour and will shine with a steady light whereas Spica will “twinkle”. The rings of Saturn are now more easily visible than in previous years as they are seen more tilted from our point of view on the Earth.
Through a small telescope, the larger moon of Saturn called Titan is well visible but the second brightest moon called Enceladus is of especial interest at the moment as the Cassini probe, currently in orbit of Saturn, has detected water vapour volcanoes on the surface of this moon. And this means that there is liquid water beneath the ice surface.
Now, when liquid water is present in combination with minerals and some heat source, primitive life can be expected and Enceladus has the potential for this. It is suspected that the entire South Pole region has a salt water ocean just below the surface and it could have existed for hundreds of millions of years. This is enough time for simple life to have developed and possibly more complicated organisms. The Cassini probe can search for this but it will take a dedicated landing mission to finally resolve the matter.
The night of May 5 to 6 is the traditional peak of the Eta Aquarid meteor shower. This shower has been observed every year since 401 AD and it is in fact dust left over from the tail of Halley’s Comet.
The Moon is full on the 6th, last quarter on the 12th, new on the 20th and first quarter on May 28.
Download the Algarve Skies Chart by clicking on the link below to download a PDF of the chart.
Clive Jackson is the Director of the Camera Obscura (next to the Castle in Tavira), specialising in education and public outreach. Tel 281 322 527, Fax 281 321 754, Email: [email protected] or visit www.cdepa.pt