| Geyser | 1991-07-23 |
|---|---|
| Echinus | 0830, 0934, 1035, 1145, 1243, 1450 |
| Emerald Spring | 1200 |
| Ledge Spring | 1140 |
| Steamboat | 1200 |
| Values for Old Faithful Area | 1991-07-23 |
|---|---|
| Astronomical Twilight Begin | 03:49 |
| Nautical Twilight Begin | 04:41 |
| Civil Twilight Begin | 05:25 |
| Sunrise | 06:00 |
| Sunset | 20:59 |
| Civil Twilight End | 21:33 |
| Nautical Twilight End | 22:17 |
| Astronomical Twilight End | 23:09 |
| Moon Illumination | 89.19% |