Eclipses glossary
What is a penumbral lunar eclipse?
Penumbral Lunar Eclipse is a lunar eclipse in which the Moon passes through Earth's penumbra but does not enter the umbra.
What it means
Penumbral Lunar Eclipse is part of eclipse geometry and timing. Eclipses require the Sun, Earth, and Moon to align near the points where the Moon's tilted orbit crosses the ecliptic. That tilt is why an eclipse does not occur at every new or full Moon.
For a deeper look with practical observing advice, read the Moonrise Moment guide to penumbral lunar eclipse.
Sources and further reading
This definition was written in plain language and checked against these science references.