| Geyser | 1999-12-29 |
|---|---|
| Grand | 0211 E, 1014 E, 1829 E |
| Great Fountain | 0150 E, 1042 E, 1949 E |
| Values for Old Faithful Area | 1999-12-29 |
|---|---|
| Astronomical Twilight Begin | 06:13 |
| Nautical Twilight Begin | 06:49 |
| Civil Twilight Begin | 07:25 |
| Sunrise | 07:59 |
| Sunset | 16:51 |
| Civil Twilight End | 17:24 |
| Nautical Twilight End | 18:01 |
| Astronomical Twilight End | 18:36 |
| Moon Illumination | 53.13% |