| Geyser | 1999-04-18 |
|---|---|
| Great Fountain | 0243 E, 1523 E |
| Values for Old Faithful Area | 1999-04-18 |
|---|---|
| Astronomical Twilight Begin | 04:46 |
| Nautical Twilight Begin | 05:26 |
| Civil Twilight Begin | 06:03 |
| Sunrise | 06:34 |
| Sunset | 20:11 |
| Civil Twilight End | 20:41 |
| Nautical Twilight End | 21:18 |
| Astronomical Twilight End | 21:58 |
| Moon Illumination | 6.4% |