| Geyser | 1999-04-01 |
|---|---|
| Great Fountain | 0938 E, 2033 E |
| Values for Old Faithful Area | 1999-04-01 |
|---|---|
| Astronomical Twilight Begin | 04:23 |
| Nautical Twilight Begin | 05:00 |
| Civil Twilight Begin | 05:35 |
| Sunrise | 06:04 |
| Sunset | 18:50 |
| Civil Twilight End | 19:19 |
| Nautical Twilight End | 19:54 |
| Astronomical Twilight End | 20:30 |
| Moon Illumination | 99.88% |