Equipment
跟踪
Tracking
Moving the gear with the sky so stars stay round.
Untracked, a 20 mm lens starts trailing near 15 seconds.
Related terms
- Star diagonal — The 90° eyepiece adapter on a refractor.
- Focal length — Distance from objective to focus.
- Field of view — How much sky you see at once, in degrees.
- Exit pupil — Aperture divided by magnification.