Septimal ruthenia: Difference between revisions

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Temperaments: ruthenium is 2.3.5.7
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The '''septimal ruthenia''' or '''septiruthenia''' ([[monzo]]: {{monzo| -263 88 0 44 }}), known as the '''44-septimal comma''' in earlier materials{{Citation needed}}, is an [[unnoticeable comma|unnoticeable]] [[7-limit]] [[comma]] of about 0.38 [[cent]]s which is defined as the difference between a stack of fourty-four [[64/63]]'s and the octave.
{{Infobox Interval
| Monzo = -263 88 0 44
| Name = septimal ruthenia, septiruthenia
| Color name = L<sup>19</sup>z<sup>44</sup>8, nela-lequadzo octave
| Comma = yes
| FJS name = -
}}
The '''septimal ruthenia''' or '''septiruthenia''' ([[monzo]]: {{monzo| -263 88 0 44 }}), known as the '''44-septimal comma''' in earlier materials<ref>The first occurrence of the name seems to be in the page of [https://en.xen.wiki/index.php?title=Unnoticeable_comma&oldid=28693 ''unnoticeable comma'', archived on October 26, 2016]. </ref>, is an [[unnoticeable comma|unnoticeable]] [[7-limit]] [[comma]] of about 0.38 [[cent]]s which is defined as the difference between a stack of fourty-four [[64/63]]'s and the octave.


It's called "ruthenia" because of the 44th element, ruthenium, following the convention of naming certain fractional-octave temperaments after chemical elements. For edos ''N'' up to ~16000, it is tempered out if and only if 44 divides ''N''. The relationship between 64/63 and one step of 44edo is highly precise, even up many thousands of edos.
It's called "ruthenia" because of the 44th element, ruthenium, following the convention of naming certain fractional-octave temperaments after chemical elements. For edos ''N'' up to ~16000, it is tempered out if and only if 44 divides ''N''. The relationship between 64/63 and one step of 44edo is highly precise, even up many thousands of edos.


== Temperaments ==
== Temperaments ==
In the full 7-limit, tempering out this comma leads to the rank-3 '''septiruthenian temperament''' (cf. ruthenium, the rank-2 2.3.5.7 temperament). You may find a list of good equal temperament supporting it below.  
In the full 7-limit, tempering out this comma leads to the rank-3 '''septiruthenic temperament''', and in the 2.3.7 subgroup, rank-2 '''septiruthenian''' temperament (cf. ruthenium, the rank-2 2.3.5.7 temperament). You may find a list of good equal temperament supporting it below. See also [[44th-octave temperaments]].


=== Septiruthenian ===
=== Septiruthenic ===
[[Subgroup]]: 2.3.5.7
[[Subgroup]]: 2.3.5.7


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Mapping generators: ~64/63, ~3, ~5
Mapping generators: ~64/63, ~3, ~5


{{Val list|legend=1| 176, 308, 352, 484, 528, 836, 1848, 2684, 4532, 7744, 8580, 9592, 10428, 12276, 14960, 27236, 42196, 99352 }}, …
{{Optimal ET sequence|legend=1| 176, 308, 352, 484, 528, 836, 1848, 2684, 4532, 7744, 8580, 9592, 10428, 12276, 14960, 27236, 42196, 99352 }}, …


[[Badness]]: 116 × 10<sup>-3</sup>
[[Badness]]: 116 × 10<sup>-3</sup>


[[Category:7-limit]]
==== Septiruthenian ====
[[Category:Unnoticeable commas]]
Subgroup: 2.3.7
 
Comma list: {{monzo| -263 88 44 }}
 
[[Mapping]]: [{{val| 44 0 263 }}, {{val| 0 1 -2 }}]
 
Mapping generators: ~64/63, ~3
 
Another notable system tempering out the septiruthenia is [[1012edo]], which is a [[zeta peak edo]].
 
== Trivia ==
Quite coincidentally, the color name for 64/63 is "Ru unison", and the 44th chemical element ruthenium, the namesake of this comma, has the symbol Ru.
 
== Notes ==
<references/>
 
[[Category:Commas named after elements]]
[[Category:Commas named after their color name]]