Editing List of brightest stars (section)

==Measurement==
The [[Sun]] is the brightest star as viewed from [[Earth]], at &minus;26.78&nbsp;mag. The second brightest is [[Sirius]] at &minus;1.46&nbsp;mag. For comparison, the brightest non-stellar objects in the [[Solar System]] have maximum brightnesses of:
*[[Moon]] &minus;12.7&nbsp;mag<ref>{{cite book
 | title=Handbook of space astronomy and astrophysics
 | first=Martin V. | last=Zombeck | date=2007
 | publisher=Cambridge University Press
 | edition=Third | pages=75, 144–145
 | location=Cambridge, UK | isbn=978-0-521-78242-5
}}</ref>
*[[Venus]] &minus;4.92&nbsp;mag
*[[Jupiter]] &minus;2.94&nbsp;mag
*[[Mars]] &minus;2.94&nbsp;mag
*[[Mercury (planet)|Mercury]] &minus;2.48&nbsp;mag
*[[Saturn]] &minus;0.55&nbsp;mag<ref name="Mallama_and_Hilton">{{cite journal
 | title=Computing apparent planetary magnitudes for The Astronomical Almanac
 | first1=Anthony | last1=Mallama | first2=James L. | last2=Hilton
 | journal=Astronomy and Computing
 | volume=25 | pages=10–24 | date=October 2018
 | doi=10.1016/j.ascom.2018.08.002 | s2cid=69912809 
 | bibcode=2018A&C....25...10M | arxiv=1808.01973 }}</ref>

Any exact order of the visual brightness of stars is not perfectly defined for four reasons:

* Stellar brightness is based on the [[apparent magnitude|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'' (separate) or ''total'' (combined) magnitude. The table is ordered by combined magnitude of all naked eye components appearing as if 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 [[binary star]] system [[Alpha Centauri]] has the total or combined magnitude of &minus;0.27, while its two component stars have magnitudes of +0.01 and +1.33.<ref name=hr>{{cite journal|title=The Bright star catalogue|year=1991|last1=Hoffleit|first1=Dorrit|last2=Jaschek|first2=Carlos|journal=New Haven|bibcode=1991bsc..book.....H}}</ref>
* New or more accurate [[photometry (astronomy)|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 [[UBV photometric system|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.<ref name=bessell>{{cite journal|title=Standard Photometric Systems|last1=Bessell|first1=Michael S.|year=2005|journal=Annual Review of Astronomy & Astrophysics|volume=43|issue=1|pages=293–336|bibcode=2005ARA&A..43..293B|doi=10.1146/annurev.astro.41.082801.100251|s2cid=28977639}}</ref> For example, [[Betelgeuse]] has the K-band ([[infrared]]) apparent magnitude of &minus;4.05.<ref name=ducati>{{cite journal|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|last1=Ducati|first1=J. R.|year=2002|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|bibcode=2002yCat.2237....0D}}</ref>
* Some stars, like [[Betelgeuse]] and [[Antares]], are [[variable star]]s, changing their magnitude over days, months or years. In the table, the range of variation is indicated with the symbol "<small>var</small>". Single magnitude values quoted for variable stars come from a variety of sources. Magnitudes shown in the table are either when the stars are at maximum brightness, which is repeated for every cycle (e.g. the eclipsing binary Algol); or, if the variations are small, a simple average magnitude. For red variable stars, specifying a single maximum brightness is often difficult because each cycle produces a different maximum brightness; this 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''<ref name="MDofA">{{cite book|last=Illingworth|first=Valerie|url=https://books.google.com/books?id=oAeyCwAAQBAJ&pg=PA237|title=Macmillan Dictionary of Astronomy|series=Dictionary Series|year=1979|publisher=Springer|isbn=9781349178032|edition=Second|location=London|publication-date=April 1985|page=237|doi=10.1007/978-1-349-17803-2|oclc=965821821|access-date=24 September 2016}}</ref> from estimated maxima 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 few selected stars, thought to be uniformly fixed in brightness, are used as [[Photometric standard stars|standard stars]].{{which|date=June 2019}} 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.<ref name=landolt>{{cite journal|title=UBVRI Photometric Standard Stars Around the Celestial Equator: Updates and Additions|last1=Landolt|first1=Arlo U.|year=2009|journal=The Astronomical Journal|volume=137|issue=5|pages=4186–4269|bibcode=2009AJ....137.4186L|arxiv=0904.0638|doi=10.1088/0004-6256/137/5/4186|s2cid=118627330}}</ref>