| Geyser | 1999-05-21 |
|---|---|
| Great Fountain | 0518 E, 1428 E |
| Values for Old Faithful Area | 1999-05-21 |
|---|---|
| Astronomical Twilight Begin | 03:38 |
| Nautical Twilight Begin | 04:31 |
| Civil Twilight Begin | 05:15 |
| Sunrise | 05:49 |
| Sunset | 20:50 |
| Civil Twilight End | 21:24 |
| Nautical Twilight End | 22:08 |
| Astronomical Twilight End | 23:01 |
| Moon Illumination | 39.63% |