天文学上的天秤座.ppt

? Libra is one of the zodiac constellation located between Virgo and Scorpio. There are more than ten pieces of this constellation can be seen by ten 8-inch (20 cm) or larger telescope. Four brightest stars in the constellation ---- α, β, γ, σ form a quadrilateral. ? Libra α Star: is called “ dixiu1 ” in chinese and Libra α is an eclipsing binary like Perseus β. ? Libra β is called “ dixiu4 ” in chinese, it is the only green star can be seen by the naked eye In the day. ? Libra's stars had been recognized since ancient times, but Ptolemy did not put it as a separate constellation. In Ptolemy ’s Constellation, it was Scorpion ’ s claw . ? Libra α is the north Scorpio claw ------ "North sequestration" ,and Libra β is the south Scorpio claw ------ “ South sequestration" ? However, until the 1st century AD Roman Caesar era, they found that it is Harvest when the sun move to these they made these stars a constellation---Libra. ? Libra can be seen out of Arctic Circle .