Observing basics
月食
Lunar eclipse
The Moon passing into Earth's shadow.
A total lunar eclipse turns the Moon dark red for over an hour.
Related terms
- Zodiacal light — Sunlight scattered by interplanetary dust, a faint cone.
- Air mass — Relative air path; 1 at zenith.
- Extinction — Atmosphere dimming starlight.
- Dark adaptation — Eyes adjusting to darkness over 20–40 minutes.