| Geyser | 1999-04-21 |
|---|---|
| Castle | 1120 E, 1959 E |
| Great Fountain | 0518 E, 1518 E |
| Values for Old Faithful Area | 1999-04-21 |
|---|---|
| Astronomical Twilight Begin | 04:40 |
| Nautical Twilight Begin | 05:20 |
| Civil Twilight Begin | 05:58 |
| Sunrise | 06:29 |
| Sunset | 20:14 |
| Civil Twilight End | 20:45 |
| Nautical Twilight End | 21:23 |
| Astronomical Twilight End | 22:04 |
| Moon Illumination | 33.05% |