Observing basics
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Conjunction
Two bodies appearing close together on the sky.
A planet–Moon conjunction often sits within 5°, easy in binoculars.
Related terms
- Astronomical darkness — Sun more than 18° below the horizon, when twilight is gone.
- Seeing — How much the atmosphere smears a star's image.
- 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.