| Geyser | 1991-08-04 |
|---|---|
| Blue | 1200 |
| Echinus | 1009, 1125, 1231, 1330, 1440, 1540 |
| Ledge Spring | 1300 |
| Steamboat | 1200 |
| Steamvalve Spring | 1200 |
| Values for Old Faithful Area | 1991-08-04 |
|---|---|
| Astronomical Twilight Begin | 04:12 |
| Nautical Twilight Begin | 04:59 |
| Civil Twilight Begin | 05:40 |
| Sunrise | 06:13 |
| Sunset | 20:45 |
| Civil Twilight End | 21:18 |
| Nautical Twilight End | 21:59 |
| Astronomical Twilight End | 22:46 |
| Moon Illumination | 41.55% |