| Values for Old Faithful Area | 1991-07-20 |
|---|---|
| Astronomical Twilight Begin | 03:44 |
| Nautical Twilight Begin | 04:37 |
| Civil Twilight Begin | 05:22 |
| Sunrise | 05:57 |
| Sunset | 21:01 |
| Civil Twilight End | 21:36 |
| Nautical Twilight End | 22:21 |
| Astronomical Twilight End | 23:15 |
| Moon Illumination | 65.89% |