| Geyser | 1981-08-13 |
|---|---|
| Arsenic | 1200 |
| Bear Den | 0845 |
| Blue | 1200 |
| Echinus | 1105 A, 1202, 1301 |
| Emerald Spring | 1200 |
| Fireball | 0904 |
| Little Whirligig | 1250 |
| Morning | 0100, 1226, 2303 |
| Pequito | 1200 |
| Pinwheel | 1200 |
| Sunday | 1200 |
| Whirligig | 0957 |
| Values for Old Faithful Area | 1981-08-13 |
|---|---|
| Astronomical Twilight Begin | 04:29 |
| Nautical Twilight Begin | 05:13 |
| Civil Twilight Begin | 05:52 |
| Sunrise | 06:24 |
| Sunset | 20:32 |
| Civil Twilight End | 21:03 |
| Nautical Twilight End | 21:42 |
| Astronomical Twilight End | 22:26 |
| Moon Illumination | 93.52% |