| Geyser | 1999-10-23 |
|---|---|
| Grand | 0105 E, 1026 E, 2059 E |
| Great Fountain | 0616 E, 1514 E |
| Values for Old Faithful Area | 1999-10-23 |
|---|---|
| Astronomical Twilight Begin | 06:11 |
| Nautical Twilight Begin | 06:45 |
| Civil Twilight Begin | 07:18 |
| Sunrise | 07:48 |
| Sunset | 18:26 |
| Civil Twilight End | 18:56 |
| Nautical Twilight End | 19:30 |
| Astronomical Twilight End | 20:03 |
| Moon Illumination | 96.33% |