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February night sky – 10pm

By Clive Jackson [email protected]

Clive Jackson is the Director of the Astronomical Observatory of Tavira (Sitio do Malhão, Tavira) and the Camera Obscura (next to the Castle in Tavira), specialising in education and public outreach.

Welcome to the February night sky. As the sky becomes fully dark during cold February evenings, low in the western horizon, we can catch our last view of the gas giant planet Jupiter in the constellation of Pisces. This planet will disappear from view by the end of the month.

For anybody who gets up really early in the morning, they can see the planet Venus, which is still visible low down on the south-eastern horizon in the constellation of Sagittarius just before sunrise. By midnight, the ringed planet Saturn becomes visible over in the east in the constellation of Virgo. This planet is over 1,400 million kilometres away and since 2005, Saturn has been closely monitored by the Cassini space probe.

The Cassini mission to Saturn is a joint project between NASA and ESA (European Space Agency). In January 2005, a landing probe called Huygens detached from Cassini and reached the surface of Titan, the largest moon of Saturn.

So far, Saturn has been found to have 62 moons but Titan is by far the largest and the most interesting as it has a dense nitrogen atmosphere and liquid methane Lakes and rivers on its surface.

In fact, Titan is the only body in our solar system, apart from Earth, where you could walk around without a spacesuit. But, you will need a face mask with an air supply as the atmosphere has no oxygen and, of course, you will have to wrap up warmly as the temperature is around 180º C below zero!

Another interesting moon of Saturn is Enceladus. This natural satellite is mainly water ice but it is warmed by tidal forces from Saturn and the others moons and this is enough to melt some of the ice to create water vapor fountains and possibly a below surface ocean.

This would be a suitable habitat for simple life to evolve and merits closer attention from space travelers in the future. The Cassini probe is nuclear powered and will be active until at least September 2017 when the mission is programmed to end. This would mean a productive life in space for this probe of more than 20 years.

This project was the largest and most expensive deep space probe NASA ever launched but I believe it will prove to be excellent value for money.

In the years to come, robot probes will provide much valuable information about our solar system but there will come a time when we have to explore in person as there really is no substitute for this. There will be dangers involved but it will be mankind’s greatest adventure.

The Moon is new on the 3rd, first quarter on the 11th, full on the 18th and last quarter on February 24.

Clive Jackson can be contacted on Tel 281 322 527,

Fax 281 321 754, Email [email protected]

or visit www.cdepa.pt