| Values for Old Faithful Area | 1977-04-20 |
|---|---|
| Astronomical Twilight Begin | 03:41 |
| Nautical Twilight Begin | 04:22 |
| Civil Twilight Begin | 04:59 |
| Sunrise | 05:30 |
| Sunset | 19:13 |
| Civil Twilight End | 19:44 |
| Nautical Twilight End | 20:22 |
| Astronomical Twilight End | 21:02 |
| Moon Illumination | 3.13% |