| Values for Old Faithful Area | 1981-08-31 |
|---|---|
| Astronomical Twilight Begin | 05:00 |
| Nautical Twilight Begin | 05:38 |
| Civil Twilight Begin | 06:15 |
| Sunrise | 06:45 |
| Sunset | 20:01 |
| Civil Twilight End | 20:31 |
| Nautical Twilight End | 21:08 |
| Astronomical Twilight End | 21:46 |
| Moon Illumination | 2.95% |