| Geyser | 1999-12-10 |
|---|---|
| Grand | 0241 E, 1520 E |
| Great Fountain | 0030 E, 1350 E |
| Values for Old Faithful Area | 1999-12-10 |
|---|---|
| Astronomical Twilight Begin | 06:03 |
| Nautical Twilight Begin | 06:38 |
| Civil Twilight Begin | 07:15 |
| Sunrise | 07:48 |
| Sunset | 16:43 |
| Civil Twilight End | 17:16 |
| Nautical Twilight End | 17:53 |
| Astronomical Twilight End | 18:28 |
| Moon Illumination | 4.83% |