Mercator's comma: Difference between revisions
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'''Mercator's comma''', '''mercator comma''', or systematically the '''53-comma''', is a [[small comma|small]] [[3-limit]] [[comma]] of about 3.62 [[cent]]s. It is the amount by which 53 [[3/2|perfect fifths]] exceed 31 [[octave]]s, in other words (3/2)<sup>53</sup>/2<sup>31</sup>. It is also the amount by which a stack of four [[Pythagorean comma]]s exceeds a [[Pythagorean limma]], the amount by which a stack of eight [[Pythagorean apotome]]s exceeds a [[27/16]] major sixth, and the amount by which a stack of two [[Pythagorean countercomma]]s fall short of the [[mystery comma]]. | |||
The comma is named for [[Nicholas Mercator]], who first took note of it as a part of his study of [[53edo]]. | The comma is named for [[Nicholas Mercator]], who first took note of it as a part of his study of [[53edo]]. | ||
== | == Temperaments == | ||
Tempering out this comma leads to the [[ | [[Tempering out]] this comma leads to the [[mercator]] temperament. For edos ''N'' up to [[8745edo|8745]], the comma is tempered out if and only if 53 divides ''N''. Examples of such edos include [[53edo]], [[159edo]], [[212edo]], [[265edo]], [[742edo]], [[954edo]] and [[1749edo]]. | ||
See [[Mercator family]] for the [[family of temperaments]] where it is tempered out. | |||
== See also == | == See also == | ||
* [[Holdrian comma#Mercator's comma, | * [[Holdrian comma #Mercator's comma, Mercator's old comma, and the Holdrian comma|Mercator's old comma]] (It is what Wikipedia calls "Mercator's comma", but it is not what most modern musicians or theorists mean by "Mercator's comma".) | ||
* [[Holdrian comma]] | * [[Holdrian comma]] | ||
* [[Unnoticeable comma]] ( | * [[Unnoticeable comma]] (its size often considered to be a threshold for it.) | ||
[[Category:Mercator]] | |||
[[Category:Commas named after mathematicians]] | [[Category:Commas named after mathematicians]] | ||
[[Category:Commas named after music theorists]] | [[Category:Commas named after music theorists]] | ||