| Geyser | 1981-07-17 |
|---|---|
| Arsenic | 1129, 1147 |
| Bear Den | 1541 |
| Constant | 1500 |
| Echinus | 1504 |
| Steamvalve Spring | 0903, 1600 ie |
| Valentine | 0851 ie, 2001 |
| Whirligig | 1546 |
| Values for Old Faithful Area | 1981-07-17 |
|---|---|
| Astronomical Twilight Begin | 03:39 |
| Nautical Twilight Begin | 04:34 |
| Civil Twilight Begin | 05:19 |
| Sunrise | 05:54 |
| Sunset | 21:04 |
| Civil Twilight End | 21:39 |
| Nautical Twilight End | 22:24 |
| Astronomical Twilight End | 23:19 |
| Moon Illumination | 100% |