| Geyser | 1999-12-15 |
|---|---|
| Grand | 0559 E, 1705 E |
| Great Fountain | 0456 E, 1539 E |
| Values for Old Faithful Area | 1999-12-15 |
|---|---|
| Astronomical Twilight Begin | 06:07 |
| Nautical Twilight Begin | 06:42 |
| Civil Twilight Begin | 07:19 |
| Sunrise | 07:52 |
| Sunset | 16:44 |
| Civil Twilight End | 17:17 |
| Nautical Twilight End | 17:54 |
| Astronomical Twilight End | 18:29 |
| Moon Illumination | 42.54% |