990/989
| Interval information |
fothutwethuloyo negative 2nd
reduced
(Shannon, [math]\sqrt{nd}[/math])
990/989 , the yerkesisma is a 43-limit superparticular comma of about 1.7 cents.
Commatic relationships
This comma is the difference between the following superparticular pairs:
It can be factored into the following superparticular ratios:
- 1001/1000 and 90000/89999
- 1045/1044 and 18792/18791
- 1089/1088 and 10880/10879
- 1105/1104 and 9504/9503
- 1197/1196 and 5720/5719
- 1377/1376 and 3520/3519
- 1463/1462 and 3060/3059
- 1496/1495 and 2925/2924
- 1764/1763 and 2255/2254
- 1936/1935 and 2025/2024
Temperaments
Tempering out this comma in the full 43-limit leads to the rank-13 temperament yerkesismic. Using the 2.3.5.11.23.43 subgroup leads to the rank-5 temperament yerkesic.
Yerkesic
Subgroup: 2.3.5.11.23.43
Comma list: 990/989
| [⟨ | 1 | 1 | 2 | 3 | 4 | 4 | ], |
| ⟨ | 0 | 1 | 0 | 0 | 0 | 2 | ], |
| ⟨ | 0 | 0 | 1 | 0 | 0 | 1 | ], |
| ⟨ | 0 | 0 | 0 | 1 | 0 | 1 | ], |
| ⟨ | 0 | 0 | 0 | 0 | 1 | -1 | ]] |
Optimal tuning (CTE): ~2 = 1\1, ~3/2 = 701.841, ~5/4 = 386.192, ~11/8 = 551.047, ~23/16 = 628.737
Optimal ET sequence: 5, 5en, 7i, 12e, 14cn, 15n, 19, 27ei, 29, 31, 46, 58i, 60en, 65, 118, 152, 183, 277, 342, 494, 677i, 836n, 1019n
Etymology
This comma was named by Francium in 2025. It refers to 990 Yerkes, the asteroid, which in turn was named after the Yerkes Observatory, where this asteroid was discovered.