| Geyser | 1999-12-27 |
|---|---|
| Grand | 0641 E, 1653 E |
| Great Fountain | 0541 E, 1640 E |
| Values for Old Faithful Area | 1999-12-27 |
|---|---|
| Astronomical Twilight Begin | 06:13 |
| Nautical Twilight Begin | 06:48 |
| Civil Twilight Begin | 07:25 |
| Sunrise | 07:58 |
| Sunset | 16:49 |
| Civil Twilight End | 17:23 |
| Nautical Twilight End | 18:00 |
| Astronomical Twilight End | 18:35 |
| Moon Illumination | 73.46% |