What is the difference between a partial and penumbral eclipse?
Quick Answer: A partial lunar eclipse happens when Earth’s shadow covers part of the Moon’s surface, making a clear dark bite. A penumbral lunar eclipse is when the Moon passes through Earth’s lighter shadow, causing a subtle dimming, often hard to notice.
Earth casts two shadows: the umbra, which is the dark, central shadow, and the penumbra, the lighter outer shadow. In a partial eclipse, the Moon enters the umbra, so you see a distinct dark curve on the Moon.
During a penumbral eclipse, the Moon only moves through the penumbra. This causes a faint shading, not a sharp shadow, so the change is subtle and easy to miss without careful observation.