| Geyser | 1987-09-20 |
|---|---|
| Blue Mud Steam Vent | 1200 |
| Values for Old Faithful Area | 1987-09-20 |
|---|---|
| Astronomical Twilight Begin | 05:29 |
| Nautical Twilight Begin | 06:04 |
| Civil Twilight Begin | 06:38 |
| Sunrise | 07:07 |
| Sunset | 19:25 |
| Civil Twilight End | 19:54 |
| Nautical Twilight End | 20:28 |
| Astronomical Twilight End | 21:04 |
| Moon Illumination | 7.87% |