| Geyser | 1987-08-23 |
|---|---|
| Blue Mud Steam Vent | 1200 |
| Dark Cavern | 1200 |
| Monarch | 1200 |
| Puff-n-Stuff | 1200 |
| Sunday | 1200 |
| Yellow Funnel Spring | 1200 |
| Values for Old Faithful Area | 1987-08-23 |
|---|---|
| Astronomical Twilight Begin | 04:46 |
| Nautical Twilight Begin | 05:27 |
| Civil Twilight Begin | 06:04 |
| Sunrise | 06:35 |
| Sunset | 20:16 |
| Civil Twilight End | 20:47 |
| Nautical Twilight End | 21:24 |
| Astronomical Twilight End | 22:05 |
| Moon Illumination | 1.47% |