| Geyser | 1981-07-23 |
|---|---|
| Arsenic | 1027, 2121 |
| Bear Den | 2100 |
| Dog's Leg Spring | 1623 |
| Echinus | 0935 |
| Moxie | 1032, 1036, 1040, 1044 |
| Whirligig | 1029, 2123 |
| Values for Old Faithful Area | 1981-07-23 |
|---|---|
| Astronomical Twilight Begin | 03:50 |
| Nautical Twilight Begin | 04:42 |
| Civil Twilight Begin | 05:26 |
| Sunrise | 06:00 |
| Sunset | 20:58 |
| Civil Twilight End | 21:33 |
| Nautical Twilight End | 22:16 |
| Astronomical Twilight End | 23:09 |
| Moon Illumination | 63% |