| Geyser | 1981-08-20 |
|---|---|
| Bear Den | 1004, 1006, 1646 ie |
| Echinus | 1140, 1223, 1533 |
| Graceful | 1500 |
| Little Whirligig | 1655 |
| Morning | 0100, 1206, 2200 |
| Rubble | 1622 A |
| Veteran | 1610 |
| Values for Old Faithful Area | 1981-08-20 |
|---|---|
| Astronomical Twilight Begin | 04:42 |
| Nautical Twilight Begin | 05:23 |
| Civil Twilight Begin | 06:01 |
| Sunrise | 06:32 |
| Sunset | 20:20 |
| Civil Twilight End | 20:51 |
| Nautical Twilight End | 21:29 |
| Astronomical Twilight End | 22:10 |
| Moon Illumination | 75.8% |