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The book was thoroughly illustrated along with observations and descriptions of the stars, their positions (copied from Ptolemy's Almagest with the longitudes increased by 12° 42' to account for the precession), their magnitudes (brightness) and their color. Notably, al-Sufi improved upon Ptolemy's system for measuring star brightness.
It includes all stars brighter than magnitude +2.50 in visible light, measured using a V-band filter in the UBV photometric system. Stars in binary systems (or other multiples) are listed by their total or combined brightness if they appear as a single star to the naked eye, or listed separately if they do not.
maximum brightness; largest moon of Saturn; [59] [60] mean opposition magnitude 8.4 [61] +8.29 star UY Scuti: seen from Earth Maximum brightness; one of largest known stars by radius +8.94: asteroid 10 Hygiea: seen from Earth maximum brightness [62] +9.50: Faintest objects visible using common 7×50 binoculars under typical conditions [63] +10
Prior to photographic methods to determine magnitude, the brightness of celestial objects was determined by visual photometric methods.This was simply achieved with the human eye by compared the brightness of an astronomical object with other nearby objects of known or fixed magnitude: especially regarding stars, planets and other planetary objects in the Solar System, variable stars [1] and ...
Other famous Arabic star catalogues include Alfraganus' A compendium of the science of stars (850) which corrected Ptolemy's Almagest; [26] and al-Sufi's Book of Fixed Stars (964) which described observations of the stars, their positions, magnitudes, brightness, and colour, drawings for each constellation, and the first known description of ...
The Bright Star Catalogue, which is a star catalogue listing all stars of apparent magnitude 6.5 or brighter, or roughly every star visible to the naked eye from Earth, contains 9,096 stars. [1] The most voluminous modern catalogues list on the order of a billion stars, out of an estimated total of 200 to 400 billion in the Milky Way .
The first list shows a few of the known stars with an estimated luminosity of 1 million L ☉ or greater, including the stars in open cluster, OB association and H II region. The majority of stars thought to be more than 1 million L ☉ are shown, but the list is incomplete. The second list gives some notable stars for the purpose of comparison.
The Yale Bright Star Catalogue has been steadily enhanced since the Yale astronomer Frank Schlesinger published the first version in 1930; even though the YBS is limited to the 9110 objects already in the catalog, the data for the objects already listed is corrected and extended, and it is appended with a comments section about the objects. The ...