Nights of Star tour in light years - The Point

The Point.fr – Published on 09/08/2013 at 07:49

The 23rd edition of this popular event will take place next weekend on the subject of understanding the distances in the universe.

How far are the stars? The 23rd edition of the Night of stars, the next weekend will be the perfect opportunity to address the issue, since the theme understanding of distances in the universe. The French Association of Astronomy (AFA), which organizes the popular event dedicated to the observation of the sky since 1991, chose this theme to the launch scheduled for the fall of the European satellite Gaia. It will aim to measure with unprecedented accuracy the distance of nearly a billion stars in the Milky Way and to draw up a 3D map of our galaxy. From Friday to Sunday, some 400 events spread throughout France will understand the importance of this mission. More than 350 nights of observation open to the public offer a “heavenly ride” night in the mountains, at the seaside or in the scrub, and even in Paris, from the panoramic rooftop terrace of the Montparnasse Tower.

astronomy clubs, tourist offices or holiday centers participating in this summer event which was also held in Belgium, Switzerland, Italy, Morocco and Algeria. The walk will begin at sunset, with the last rays disappear in the northwest horizon. Early in the night, telescopes and glasses will be focused on a crescent moon and the public can watch the sunset Venus, the evening star. Twilight installed, the three stars of “Summer Triangle”, Vega, Deneb and Altair, will unfold at its zenith, while the ringed planet, Saturn, plunge to the west.

A smartphone application

By observing the sky, difficult to perceive that the “three beautiful summer” are so far from each other. Altair and Vega are closest, respectively 17 and 25 light years. Deneb, it lies nearly 1,550 light-years. The tour will continue through the constellations of the Milky Way, Cassiopeia in Scorpio, through Cygnus and Sagittarius. It would not be complete without visiting the famous Perseids meteor which the peak activity is expected at this time of the year. Meteors called by astronomers, these small solid objects, or tiny pebbles rock dust, tumble at a speed of about 210 000 km / h in the atmosphere where they are consumed. When they enter the atmosphere, the temperature rises to 2000 ° C, producing visible to the naked eye light trails.

To observe, “a sun and your eyes enough,” said Afa, stressing that “the single eye vision offers a wide will return the extent of the phenomenon. ” Astronomers still advise to choose an open area away from city lights. Show guaranteed … if the weather does not play spoilsport. The program of events is available on the www.afanet.fr / nights site. For its part, the television channel Arte offer Saturday a “Day of Stars” with a series of documentaries from 12 h 50 (The Sun in all its forms) and until late evening (Star Stories) . Finally the application for smartphones and tablets “Night of the Stars, Volume 1″ available on Iphone, Ipad and Android is free until August 12. This “sky tour” continues the theme of the distances of the universe, said the company CosmoStory.