| Geyser | 1981-08-30 |
|---|---|
| Bear Den | 1958 |
| Blue Mud Steam Vent | 1200 |
| Branch Spring | 1200 |
| Echinus | 1028, 1244 A, 1328:49, 1418:26, 1550 |
| Graceful | 1500 |
| Little Whirligig | 1350 ie, 1602 |
| Morning | 0051, 0630 |
| Whirligig | 2040 |
| Values for Old Faithful Area | 1981-08-30 |
|---|---|
| Astronomical Twilight Begin | 04:59 |
| Nautical Twilight Begin | 05:37 |
| Civil Twilight Begin | 06:13 |
| Sunrise | 06:43 |
| Sunset | 20:03 |
| Civil Twilight End | 20:33 |
| Nautical Twilight End | 21:10 |
| Astronomical Twilight End | 21:48 |
| Moon Illumination | 0.47% |