| Geyser | 1999-04-12 |
|---|---|
| Great Fountain | 0638 E, 1818 E |
| Values for Old Faithful Area | 1999-04-12 |
|---|---|
| Astronomical Twilight Begin | 04:59 |
| Nautical Twilight Begin | 05:38 |
| Civil Twilight Begin | 06:14 |
| Sunrise | 06:44 |
| Sunset | 20:03 |
| Civil Twilight End | 20:33 |
| Nautical Twilight End | 21:09 |
| Astronomical Twilight End | 21:48 |
| Moon Illumination | 19.78% |