| Geyser | 1981-08-01 |
|---|---|
| Arsenic | 1233 |
| Basin | 1800 |
| Echinus | 1608, 1830 A |
| Giantess | 2136 |
| Guardian | 1224 |
| Morning | 0100, 1043, 2218 |
| Valentine | 1235 |
| Veteran | 1508, 1730 |
| Values for Old Faithful Area | 1981-08-01 |
|---|---|
| Astronomical Twilight Begin | 04:07 |
| Nautical Twilight Begin | 04:55 |
| Civil Twilight Begin | 05:37 |
| Sunrise | 06:10 |
| Sunset | 20:48 |
| Civil Twilight End | 21:21 |
| Nautical Twilight End | 22:03 |
| Astronomical Twilight End | 22:51 |
| Moon Illumination | 1.49% |