วิธีการคำนวณ Sunset Time
learn.whatIsHeading
A sunset calculator computes the exact time of sunset and civil twilight for any location and date using solar position algorithms.
สูตร
Sunset time depends on latitude, longitude, date, and refraction. Uses NOAA algorithm or lookup tables.
- φ
- Latitude (degrees)
- λ
- Longitude (degrees)
- t
- Sunset time (local time (HH:MM))
คำแนะนำทีละขั้นตอน
- 1Based on solar declination, hour angle, and observer latitude/longitude
- 2Civil twilight ends when sun is 6° below horizon
- 3Nautical twilight: 12°; Astronomical twilight: 18°
- 4Equation of Time accounts for Earth's elliptical orbit
ตัวอย่างที่มีคำตอบ
อินพุต
London (51.5°N), 21 December 2025
ผลลัพธ์
Sunset ≈ 15:58 GMT; Civil twilight ends ≈ 16:32 GMT
คำถามที่พบบ่อย
Why does sunset time change throughout the year?
Earth's axial tilt. Summer: sun higher arc, sets later. Winter: sun lower arc, sets earlier.
Is sunset time the same everywhere?
No. Latitude determines sun angle. Longitude determines time zone. Terrain (hills, mountains) can block sun.
What's the difference between sunset and twilight?
Sunset: sun touches horizon. Civil twilight: 6° below horizon (still light). Nautical: 12° below (navigational).