Observing basics
掩星
Occultation
A nearer body hiding a farther one.
Lunar occultations probe the Moon's limb.
Related terms
- Air mass — Relative air path; 1 at zenith.
- Extinction — Atmosphere dimming starlight.
- Dark adaptation — Eyes adjusting to darkness over 20–40 minutes.
- Averted vision — Looking slightly off-target to use rod-rich retina.