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Stars in the night sky. The first star catalogue in Greek astronomy was created by Aristillus in approximately 300 BC, with the help of Timocharis. [10] The star catalog of Hipparchus (2nd century BC) included 1,020 stars, and was used to assemble Ptolemy's star catalogue. [11] Hipparchus is known for the discovery of the first recorded nova ...
For example, the binary star system Alpha Centauri has the total or combined magnitude of −0.27, while its two component stars have magnitudes of +0.01 and +1.33. [3] New or more accurate photometry, standard filters, or adopting differing methods using standard stars can measure stellar magnitudes slightly differently. This may change the ...
Pogson's original 1856 paper defined magnitude 6.0 to be the faintest star the unaided eye can see, [11] but the true limit for faintest possible visible star varies depending on the atmosphere and how high a star is in the sky. The Harvard Photometry used an average of 100 stars close to Polaris to define magnitude 5.0. [12] Later, the Johnson ...
The following is a list of particularly notable actual or hypothetical stars that have their own articles in Wikipedia, but are not included in the lists above. BPM 37093 — a diamond star Cygnus X-1 — X-ray source
Second brightest star in the night sky. Gacrux (γ Crucis) 73 [93] L/T eff: Twenty-sixth brightest star in the night sky. Polaris (α Ursae Minoris) 46.27 ± 0.42 [94] AD The current star in the North Pole. It is a Classical Cepheid variable, and the brightest example of its class. Aldebaran (α Tauri) 45.1 ± 0.1 [95] AD Fourteenth brightest ...
For example, 3C 273 has an average apparent magnitude of 12.8 (when observing with a telescope), but an absolute magnitude of −26.7. If this object were 10 parsecs away from Earth it would appear nearly as bright in the sky as the Sun (apparent magnitude −26.744).
The bright star at top center is Alhena, which forms a cross-shaped asterism with the Winter Triangle. With an apparent magnitude of −1.46, Sirius is the brightest star in the night sky, almost twice as bright as the second-brightest star, Canopus. [72]
This number is likely much higher, due to the sheer number of stars needed to be surveyed; a star approaching the Solar System 10 million years ago, moving at a typical Sun-relative 20–200 kilometers per second, would be 600–6,000 light-years from the Sun at present day, with millions of stars closer to the Sun.