| Geyser | 1999-02-21 |
|---|---|
| Great Fountain | 0453 E, 1523 E |
| Values for Old Faithful Area | 1999-02-21 |
|---|---|
| Astronomical Twilight Begin | 05:37 |
| Nautical Twilight Begin | 06:10 |
| Civil Twilight Begin | 06:44 |
| Sunrise | 07:13 |
| Sunset | 17:59 |
| Civil Twilight End | 18:29 |
| Nautical Twilight End | 19:03 |
| Astronomical Twilight End | 19:36 |
| Moon Illumination | 29.64% |