Partial Lunar Eclipse on Sat, 21 December 1991 – Path & Viewing Guide
Global Eclipse Conditions
A partial lunar eclipse occurs when only part of the Moon enters Earth's darker umbral shadow. The eclipse begins with a subtle penumbral phase at 23:29 (GMT-9), which may be hard to detect without instruments. The visible partial phase starts at 01:01, when Earth’s umbra begins to cover a portion of the lunar surface, creating a distinct dark bite on the Moon.At 01:36, the eclipse reaches its peak, with up to 4% of the Moon covered by Earth’s shadow. After this, the shadow gradually recedes, and the partial phase ends at 02:08. The eclipse concludes with the Moon exiting the penumbra at 03:39.
Local Eclipse Phase Times
| Phase | Time (GMT-9) | Local Visibility |
|---|---|---|
| Penumbral Eclipse Begins | 23:29 | 👁 |
| Partial Eclipse Begins | 01:01 | 👁 |
| The maximum eclipse occurs at 01:36. The eclipse is partial with 4% coverage. | ||
| Partial Eclipse Ends | 02:08 | 👁 |
| Penumbral Eclipse Ends | 03:39 | 👁 |
Global Eclipse Path
Local Eclipse Conditions at (GMT-9)
Earth's Shadow and Moon relative positions.
Local Eclipse Parameters
| Eclipse Phase | |
| Penumbral Magnitude | |
| Umbral Magnitude | |
| Penumbral Coverage | |
| Umbral Coverage | |
| Umbra Size, km | |
| Penumbra Size, km | |
| Distance to Shadow Center, km |
Observation Parameters
| Time | |
| Latitude | 37.3541 |
| Longitude | -121.955 |
| Moon Elevation | -121.955 |
| Moon Azimuth | -121.955 |