| Geyser | 1999-12-12 |
|---|---|
| Grand | 0011 E, 1114 E, 2153 E |
| Great Fountain | 0310 E, 1306 E, 2150 E |
| Values for Old Faithful Area | 1999-12-12 |
|---|---|
| Astronomical Twilight Begin | 06:04 |
| Nautical Twilight Begin | 06:40 |
| Civil Twilight Begin | 07:17 |
| Sunrise | 07:50 |
| Sunset | 16:43 |
| Civil Twilight End | 17:16 |
| Nautical Twilight End | 17:53 |
| Astronomical Twilight End | 18:28 |
| Moon Illumination | 16.1% |