Annotations of elementary astronomical observation


Posts Tagged ‘Open clusters

The Pleiades open cluster

Posted by: bitacoradegalileo on: July 21, 2011

WHAT ARE OPEN CLUSTERS? Open clusters are groups of tens, hundreds or thousands of stars originated in the same cloud of gas. Often the gas is gone, in whole or in part, because the radiation emitted by the brightest stars and his appearance is that of an irregular splash of bright spots, with no general structure and asymmetric. The hosted stars are generally young (a few hundred million years; compare with the 4,000 million of the Sun), massive and very hot. They are scattered on sizes in the order of thirty light-years, and are slowly dispersed by the tidal […]

Orion, the Cathedral of the Sky

Posted by: bitacoradegalileo on: July 19, 2011

Orion is undoubtedly the most famous constellation in the sky of winter, and one of the best known among the 88 currently recognized by the IAU (International Astronomical Union). Its bright stars visible from both hemispheres make this constellation globally recognized and in my opinion the most fascinating. It has been called “The Cathedral of Heaven“, a name which I subscribe enthusiastically. It is located right in the middle of the celestial equator, and is used as a reference for others, as we shall see. Orion resembles a person. First, try to […]