Tool

Earth-motion calculator

Date, latitude, longitude. Outputs: solar declination, noon altitude, sunrise/sunset in local solar time, day length, season, day of year, and the tilt you chose. School geometry — not a sextant. SI first.

Linked labs: Why seasons happen · Solar altitude

DateDay of year · 288

Place ANameLatitude °Longitude °

Axial tilt (teaching switch)

Equation of time (off by default). Clocks can differ by about 16 minutes from local solar noon.

London

51.51°N 0.13°W

Declination: -9.60°
Noon altitude: 28.9°
Sunrise (solar): 06:50
Sunset (solar): 17:11
Day length: 10.36 h
Season: Northern winter
Day of year: 288
Tilt used: 23.44°

London

Noon altitude 28.9°

Day length 10.36 h

Ice ring = terminator (day–night). It walks with the date slider and the tilt switch. Click the Earth to set Place A. Orbit radius is a classroom lie; tilt is true.

Earth from orbit with a sharp day-night terminator. — June and December are opposite tilts, not opposite distances. The terminator walks.NASA, public domain

A long-exposure sun path over a horizon, an analemma-like arc. — Noon altitude is 90° − |φ − δ|. Analemma is optional; equation of time is the clock error.Wikimedia Commons / public domain