| Geyser | 1999-12-23 |
|---|---|
| Grand | 0944 E, 2050 E |
| Great Fountain | 0210 E, 1259 E |
| Values for Old Faithful Area | 1999-12-23 |
|---|---|
| Astronomical Twilight Begin | 06:11 |
| Nautical Twilight Begin | 06:47 |
| Civil Twilight Begin | 07:23 |
| Sunrise | 07:57 |
| Sunset | 16:47 |
| Civil Twilight End | 17:20 |
| Nautical Twilight End | 17:57 |
| Astronomical Twilight End | 18:33 |
| Moon Illumination | 99.53% |