Sidereal comma

Interval information

Ratio	366/365
Subgroup monzo	2.3.5.61.73 [1 1 -1 1 -1⟩
Size in cents	4.736621¢
Name	Sidereal comma
FJS name	[math]\displaystyle{ \text{P1}^{61}_{5,73} }[/math]
Special properties	superparticular, reduced
Tenney norm (log2 nd)	17.0275
Weil norm (log2 max(n, d))	17.0314
Wilson norm (sopfr(nd))	144
Comma size	small
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The sidereal comma (ratio: 366/365, monzo: [1 1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 -1⟩) is a small 73-limit comma. It is the difference between 73/61 and 6/5.

Etymology

This comma was named by Frostburn in 2024 in reference to the year lasting (roughly) 366 sidereal days but only 365 solar days. Taking leap years and associated effects into account the ratio is actually closer to 9156/9131, but 366/365 is more recognizable numerically.