| Geyser | 1999-12-09 |
|---|---|
| Giant | 1258 |
| Grand | 1159 E |
| Great Fountain | 0502 E, 1501 E |
| Values for Old Faithful Area | 1999-12-09 |
|---|---|
| Astronomical Twilight Begin | 06:02 |
| Nautical Twilight Begin | 06:37 |
| Civil Twilight Begin | 07:14 |
| Sunrise | 07:47 |
| Sunset | 16:43 |
| Civil Twilight End | 17:16 |
| Nautical Twilight End | 17:53 |
| Astronomical Twilight End | 18:28 |
| Moon Illumination | 1.6% |