| Geyser | 1981-09-21 |
|---|---|
| Arsenic | 0950 |
| Values for Old Faithful Area | 1981-09-21 |
|---|---|
| Astronomical Twilight Begin | 05:31 |
| Nautical Twilight Begin | 06:06 |
| Civil Twilight Begin | 06:40 |
| Sunrise | 07:09 |
| Sunset | 19:23 |
| Civil Twilight End | 19:51 |
| Nautical Twilight End | 20:26 |
| Astronomical Twilight End | 21:01 |
| Moon Illumination | 45.39% |