| Geyser | 1931-10-21 |
|---|---|
| Emerald Spring | 1200 |
| Values for Old Faithful Area | 1931-10-21 |
|---|---|
| Astronomical Twilight Begin | 05:08 |
| Nautical Twilight Begin | 05:42 |
| Civil Twilight Begin | 06:15 |
| Sunrise | 06:45 |
| Sunset | 17:30 |
| Civil Twilight End | 18:00 |
| Nautical Twilight End | 18:34 |
| Astronomical Twilight End | 19:07 |
| Moon Illumination | 76.94% |