| Geyser | 1999-12-16 |
|---|---|
| Grand | 0411 E, 1608 E |
| Great Fountain | 0245 E, 1243 E, 2242 E |
| Values for Old Faithful Area | 1999-12-16 |
|---|---|
| Astronomical Twilight Begin | 06:07 |
| Nautical Twilight Begin | 06:43 |
| Civil Twilight Begin | 07:20 |
| Sunrise | 07:53 |
| Sunset | 16:44 |
| Civil Twilight End | 17:17 |
| Nautical Twilight End | 17:54 |
| Astronomical Twilight End | 18:30 |
| Moon Illumination | 52.92% |