This is a list of stars down to magnitude +2.50, as determined by their maximum, total, or combined visual magnitudes as viewed from Earth. Although several of the brightest stars are known binary or multiple star systems and are relatively close to Earth, they appear to the naked eye as single stars. The list below combines/adds the magnitudes of bright individual components. Most of the proper names in this list are those approved by the Working Group on Star Names. Popular star names here that have not been approved by the IAU appear with a short note.
Measurement
The Sun is the brightest star as viewed from Earth. The apparent visual magnitudes of the brightest stars can also be compared to non-stellar objects in our Solar System. Here the maximum visible magnitudes above the second brightest star, Sirius, are as follows. Excluding the Sun, the brightest objects are the Moon, Venus, Jupiter, Mars, Mercury, and Saturn. Any exact order of the visual brightness of stars is not perfectly defined for four reasons:
Stellar brightness is traditionally based on the apparent visual magnitude as perceived by the human eye, from the brightest stars of 1st magnitude to the faintest at 6th magnitude. Since the invention of the optical telescope and the documenting of binary stars and multiple star systems, stellar brightness could be expressed as either individual or total magnitude. The table is ordered by combined magnitude of all naked eye components appearing as if it they were single stars. Such multiple star systems are indicated by parentheses showing the individual magnitudes of component stars bright enough to make a detectable contribution. For example, the double star Alpha Centauri has the total or combined magnitude of −0.27, while its two component stars have magnitudes of +0.01 and +1.33.
New or more accurate photometry, standard filters, or adopting differing methods using standard stars can measure stellar magnitudes slightly differently. This may change the apparent order of lists of bright stars. The table shows measured V magnitudes, which use a specific filter that closely approximates human vision. However, other kinds of magnitude systems do exist based on different wavelengths, some well away from the distribution of the visible wavelengths of light, and these apparent magnitudes vary dramatically in the different systems. For example, Betelgeuse has the K-band apparent magnitude of −4.05.
Some stars, like Betelgeuse and Antares, are variable stars, changing their magnitude over days, months or years. In the table, the range of variation is indicated with var. Single magnitude values quoted for variable stars come from a variety of sources. Magnitudes are expressed within the table are when the stars are either at maximum brightness, which is repeated for every cycle, e.g., the eclipsing binary Algol; or, if the variations are small, as a simple average magnitude. For all red variable stars, describing a single maximum brightness is often difficult because each cycle produces a different maximum brightness, which is thought to be caused by poorly understood pulsations in stellar evolution processes. Such quoted stellar brightness is sometimes based on the average maximum apparent magnitude from estimated maximums over many observed light-curve cycles, sometimes spanning across centuries. Results often quoted in the literature are not necessarily straightforward and may differ in expressing an alternate value for a singular maximum brightness or as a range of values.
A select number of stars, thought to be uniformly fixed in brightness, are used as standard stars. These standard stars have carefully determined magnitudes that have been analysed over many years, and are often used to determine other stars' magnitudes or their stellar parameters using comparatively consistent scales.
Main table
The source of magnitudes cited in this list is the linked Wikipedia articles—this basic list is a catalog of what Wikipedia itself documents. References can be found in the individual articles. ;Spatial distribution of these stars The 92 stars listed above are in 38 modern constellations, in turn covering 61.1% of our surrounds. As drawn, diminutive Crux, which has three of these stars is the most densely populated as to these stars. Virgo and Hydra have one such star yet more than 3% each of the night sky associated with them by professional astronomers, as these constellation's limits have been drawn by the IAU. Among the 50 constellations with none of these, Hercules is the largest, covering 2.97% of the galactic and extra-galactic surrounds.
