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ed , of which only 6 or 7 are visible to the the to visible are 7 or 6 only which of stars, ed hundr they flew into the forming a cluster of stars. of cluster a forming sky the into flew they about 100 stars and lies at the center of the Cancer the of center the at lies and stars 100 about

Taurus. It contains a large amount of dust and several several and dust of amount large a contains It . converted them into doves to help them escape, and and escape, them help to doves into them converted known since ancient times. Praesepe is made up of of up made is Praesepe times. ancient since known

time, with a given chemical composition. chemical given a with time, . The belongs to the zodiacal constellation constellation zodiacal the to belongs Pleiades The years. pursued them for many years. eventually eventually Zeus years. many for them pursued bees. It is easily visible to the naked eye, and thus thus and eye, naked the to visible easily is It bees.

gravitationally bound and that were born at the same same the at born were that and bound gravitationally is much older, with an estimated age of 4500 million million 4500 of age estimated an with older, much is hunter was in love with the young women and and women young the with love in was Orion hunter its round and fuzzy shape reminds us of a swarm of of swarm a of us reminds shape fuzzy and round its

A cluster is a group of typically 100 stars that are are that stars 100 typically of group a is cluster A very young as far as ages are concerned. Our Earth Our concerned. are ages star as far as young very ), daughters of and . The great great The Pleione. and Atlas of daughters Sterope), commonly referred to as the "Beehive" cluster, because because cluster, "Beehive" the as to referred commonly

light years and is around 100 million years old. This is is This old. years million 100 around is and years light (, , , , , , and and Celaeno, Taygete, Merope, Electra, Maia, (Alcyone, has an estimated age of 650 million years. Praesepe is is Praesepe years. million 650 of age estimated an has

The Pleiades cluster lies at a distance of about 375 375 about of distance a at lies cluster Pleiades The In , the Pleiades were 7 sisters sisters 7 were Pleiades the mythology, Greek In The Praesepe cluster lies at about 587 light years and and years light 587 about at lies cluster Praesepe The

Praesepe Pleiades

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Hipparcos and In 1989, the launched Hipparcos, a satellite that has revolutionised our The Little Books of Gaia knowledge of the to which we belong, the . It measured very precise distances and positions of stars near the to create a three dimensional picture of that region of the Galaxy. The stereoscopic images shown here have been created using data from A 3-D the Hipparcos mission. ESA plans to launch, in spring 2012, a satellite called Gaia which will also measure distances and positions of stars, but now to much TOUR OF higher accuracy and including stars right across our Milky Way and beyond. OUR How to view the 3-D images Each pair of images in this booklet represents a star field of about 6 by 6 degrees. For viewing these images GALAXY in three dimensions with the "fused" free-eye imaging method, the following recommendations may help. View the page from a distance of about 30-50 cm under good and uniform lighting conditions. Focus on the images, but "relax" the eyes so that they converge at infinity Gaia Arcturus lies at a distance of about 36 light years. It is The easiest way to find Arcturus is (imagine that you are staring through the paper at a the brightest star of the northern hemisphere and the to start with the (the Plough). distant point, so that the left eye observes and focuses fourth brightest star in the entire sky. In Greek, Follow the handle of the Big Dipper as it on the left image, while the right eye focuses on the Arcturus means "Guardian of the ", a name given to arcs and keep going until you come to right image). Fix on a particular object until the depth this star because of its proximity to the a bright star. That's Arcturus. "Follow effect appears: when it does, the results are dramatic. (Great Bear) constellation. Arcturus belongs to the the arc to Arcturus", as the old Bootes constellation, which forms a kite-shaped stargazer's saying goes. pattern in the sky. Arcturus More detailed information can be found on the 5 6 Gaia web site: http://sci.esa.int/Gaia June 2009