| Geyser | 1991-08-20 |
|---|---|
| Blue | 1200 |
| Crater Spring | 1200 |
| Echinus | 0855, 1005, 1108, 1200, 1205, 1306, 1401, 1506, 1602, 1705 |
| Minute | 1200 |
| Morning | 0830, 1225, 1622, 2003, 2329 E |
| Steamboat | 1200 |
| Values for Old Faithful Area | 1991-08-20 |
|---|---|
| Astronomical Twilight Begin | 04:41 |
| Nautical Twilight Begin | 05:22 |
| Civil Twilight Begin | 06:00 |
| Sunrise | 06:31 |
| Sunset | 20:21 |
| Civil Twilight End | 20:52 |
| Nautical Twilight End | 21:30 |
| Astronomical Twilight End | 22:11 |
| Moon Illumination | 77.48% |