Observing the Sky from 40°N

A constellation is a group of celestial bodies, usually stars, which appear to form a pattern in the sky. Astronomers today still utilize the term, though the current system focuses primarily on constellations as grid-like segments of the celestial sphere rather than as patterns. A star-pattern that is not officially classed as a constellation is referred to as an asterism. One famous example is the asterism known as the Big Dipper, a term unused by the International Astronomical Union (IAU) as the stars are considered part of the larger constellation of Ursa Major. 

The stars within a constellation rarely have any substantial astrophysical relationship to each other, and their apparent proximity when viewed from Earth disguises the fact that they typically lie light years apart. However, there are some exceptions: in the constellation of Ursa Major, the Big Dipper is almost entirely constituted by stars approximate to one another, belonging to a stellar group known as the Ursa Major Moving Group.




https://en.wikibooks.org/wiki/Observing_the_Sky_from_40%C2%B0N/Introduction

Comments

Post a Comment

Popular posts from this blog

Abell 2142 - most massive object in the Universe?

Image
Abell 2142, or A2142 , is a huge, X-ray luminous galaxy cluster in the constellation Corona Borealis . It is the result of a still ongoing merger between two galaxy clusters. The combined cluster is six million light years across, contains hundreds of galaxies and enough gas to make a thousand more. It is "one of the most massive objects in the universe." [1]   https://en.wikipedia.org/wiki/Abell_2142 Portal >>>
Read more

Schiaparelli (SkiAppUhRelEE)

Image
Schiaparelli EDM lander [skjapaˈɾɛlːi] was the Entry, Descent and Landing Demonstrator Module (EDM) of the ExoMars programme—a joint mission of the European Space Agency (ESA) and the Russian space agency Roscosmos . [4] It was built in Italy and was intended to test technology for future soft landings on the surface of Mars . [5] It also had a limited but focused science payload that would have measured atmospheric electricity on Mars and local meteorological conditions. [2] [6] [7] https://en.wikipedia.org/wiki/Schiaparelli_EDM_lander   Portal  
Read more

Solar System

Image
The Solar System [a] is the gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly. [b] Of those objects that orbit the Sun directly, the largest eight are the planets , [c] with the remainder being significantly smaller objects, such as dwarf planets and small Solar System bodies . Of the objects that orbit the Sun indirectly, the moons , two are larger than the smallest planet, Mercury . [d] The Solar System formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud . The vast majority of the system's mass is in the Sun, with most of the remaining mass contained in Jupiter . The four smaller inner planets, Mercury , Venus , Earth and Mars , are terrestrial planets , being primarily composed of rock and metal. The four outer planets are giant planets , being substantially more massive than the terrestrials. The two largest, Jupiter and Saturn , are gas giants , being compose...
Read more