| Geyser | 1981-07-18 |
|---|---|
| Bear Den | 0406 |
| Blue | 1100, 1509 |
| Dark Cavern | 0406, 1410 |
| Echinus | 0619 |
| Guardian | 1420 |
| Veteran | 0850 |
| Values for Old Faithful Area | 1981-07-18 |
|---|---|
| Astronomical Twilight Begin | 03:41 |
| Nautical Twilight Begin | 04:35 |
| Civil Twilight Begin | 05:20 |
| Sunrise | 05:55 |
| Sunset | 21:03 |
| Civil Twilight End | 21:38 |
| Nautical Twilight End | 22:23 |
| Astronomical Twilight End | 23:17 |
| Moon Illumination | 98.82% |