如何计算Sunrise & Sunset Times

learn.whatIsHeading

A sunrise/sunset calculator computes the times of sunrise, sunset, solar noon, and day length for any location and date. Times vary with latitude, longitude, and time of year due to Earth's axial tilt and orbital position.

分步指南

1. 1Solar declination: the angle between the sun and the equatorial plane (varies −23.5° to +23.5°)
2. 2Hour angle: the sun's position relative to solar noon
3. 3Sunrise/sunset occur when the sun is at −0.833° (accounting for refraction and sun's radius)
4. 4Algorithm based on Jean Meeus's "Astronomical Algorithms"

例题解析