Editing Bayer designation (section)

==Orion as an example==
In [[Orion (constellation)|Orion]], Bayer first designated [[Betelgeuse]] and [[Rigel]], the two 1st-magnitude stars (those of magnitude 1.5 or less), as Alpha and Beta from north to south, with Betelgeuse (the shoulder) coming ahead of Rigel (the foot), even though the latter is usually the brighter. (Betelgeuse is a variable star and can at its maximum occasionally outshine Rigel.)<ref>{{cite book|author=Patrick Moore|title=Brilliant Stars|url=https://books.google.com/books?id=uWEOGwAACAAJ|year=1996|publisher=Cassell|isbn=978-0-304-34903-6}}</ref> Bayer then repeated the procedure for the stars of the 2nd magnitude, labeling them from ''gamma'' through ''zeta'' in "top-down" (north-to-south) order. Letters as far as Latin ''p'' were used for stars of the sixth magnitude.
[[Image:Orion constellation map.svg|upright=1.4|right|thumb|[[Orion (constellation)|Orion]] constellation map]]
{| class="wikitable"
|+ {{nowrap|Bayer's brightest three classes of stars in Orion}}
! Bayer<br/>Designation || Bayer's class || Apparent<br/>Magnitude || Proper<br/>Name 
|-
| [[α Orionis]]
| First
| 0.45
| Betelgeuse
|-
| [[β Orionis]]
| First
| 0.18
| Rigel
|-
| [[γ Orionis]]
| Second
| 1.64
| Bellatrix
|-
| [[δ Orionis]]
| Second
| 2.23
| Mintaka
|-
| [[ε Orionis]]
| Second
| 1.69
| Alnilam
|-
| [[ζ Orionis]]
| Second
| 1.70
| Alnitak
|-
| [[η Orionis]]
| Third
| 3.42
| Algjebbah
|-
| [[θ Orionis]]
| Third
|
| (Orion nebula)
|-
| [[ι Orionis]]
| Third
| 2.77
| Hatysa
|-
| [[κ Orionis]]
| Third
| 2.07
| Saiph
|}
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==Various arrangements==
{{Disputed-section|date=May 2019}}
The "First to Rise in the East" order is used in a number of instances.  [[Castor (star)|Castor]] and [[Pollux (star)|Pollux]] of [[Gemini (constellation)|Gemini]] may be an example of this: Pollux is brighter than Castor, but the latter rises earlier and was assigned ''alpha''. In this case, Bayer may also have been influenced by the traditional order of the mythological names "[[Castor and Pollux]]": Castor is generally named first whenever the twins are mentioned.

Although the brightest star in Draco is Eltanin ([[Gamma Draconis]]), [[Thuban]] was assigned ''alpha'' (α) by Bayer because, due to [[precession]], Thuban was the [[pole star|north pole star]] 4,000 years ago.<ref name="MOORE">{{Cite book| title=The Observer's Year: 366 Nights in the Universe| author=Moore, Patrick| page=283| year=2005| isbn=9783540761471|url=https://books.google.com/books?id=ZnDvAAAAMAAJ&q=thuban}}</ref> Sometimes there is no apparent order, as exemplified by the stars in [[Sagittarius (constellation)|Sagittarius]], where Bayer's designations appear almost random to the modern eye. [[Alpha Sagittarii|Alpha]] and [[Beta Sagittarii]] are perhaps the most anomalously designated stars in the sky. They are more than two magnitudes fainter than the brightest star (designated [[Epsilon Sagittarii|Epsilon]]), they lie several degrees south of the main pattern (the "teapot" [[asterism (astronomy)|asterism]]), they are more than 20 degrees off the [[ecliptic]] in a [[Zodiac]]al constellation, and they do not even rise from Bayer's native Germany (while Epsilon and several other brighter stars do). The order of the letters assigned in Sagittarius does correspond to the magnitudes as illustrated on Bayer's chart; but the latter do not agree with modern determinations of the magnitudes.

Bayer designations added by later astronomers generally were ordered by magnitude, but care was usually taken to avoid conflict with designations already assigned.  In Libra, for example, the new designations sigma, tau, and upsilon were chosen to avoid conflict with Bayer's earlier designations, even though several stars with earlier letters are not as bright.
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