Counterquectisma
| Factorization | 2-500 × 3314 × 5 |
| Monzo | [-500 314 1⟩ |
| Size in cents | 0.1839856¢ |
| Names | counterquectisma, deltapion comma, |
| Color name | Quintritrilayo comma |
| FJS name | [math]\text{45d}{-31}^{5}[/math] |
| Special properties | reduced |
| Tenney height (log2 nd) | 1000 |
| Weil height (log2 max(n, d)) | 1000 |
| Wilson height (sopfr (nd)) | 1947 |
| Harmonic entropy (Shannon, [math]\sqrt{n\cdot d}[/math]) |
~2.39764 bits |
| Comma size | unnoticeable |
| open this interval in xen-calc | |
Counterquectisma, alternately deltapion comma, is an unnoticeable 5-limit comma.
Temperaments
It is associated with systems which have a precise perfect fifth, such as 359edo and 665edo. Tempering it out in the 5-limit produces rank-2 counterquectismic temperament. Equal tempereaments tempering out this comma include 359, 665, 1024, 1689, 3684, 4349, 7368, 8033.
Etymology
The comma was named by Eliora. First name derives from comma's monzo, number 500 being D in roman numerals, and phonetic alphabet for D is "delta", to which "pi" is added to signify 314, the decimal expansion of pi. The second name is by analogy with quectisma, meaning that both are the same commas that reach 5/4 from a different angle, with two mappings converging from opposite ends in 665edo.