Observing basics
距角
Elongation
Angular distance from the Sun for an inner planet.
Venus reaches about 47°, so it only shows near dawn or dusk.
Related terms
- Transparency — How well the sky passes starlight, set by water vapour and dust.
- Light pollution — Artificial light brightening the night sky and hiding faint objects.
- Bortle scale — A 1–9 scale describing how dark a night sky is.
- Magnitude — A logarithmic brightness scale: smaller numbers are brighter.