ATRONOMY – PLANETARY CIENCE (52) CALCULATOR
Moon Rise Set
A precise tool.
What is the Moon Rise Set & How does it work?
The Moon follows a complex orbit around Earth, inclined about 5° to the ecliptic. Because of this inclination and the Earth’s rotation, the Moon appears to rise in the east and set in the west at different times each day. The exact moments of moonrise and moonset depend on the observer’s geographic latitude ((phi)), longitude, the Moon’s declination ((delta)) at the given date, and the local time‑zone offset. Atmospheric refraction and the Moon’s apparent radius also shift the observed times by a few minutes. Astronomers compute the hour angle at rise/set ((H_0)) using spherical trigonometry. Once (H_0) is known, it is converted to universal time and then adjusted for the observer’s longitude and time‑zone to obtain the local rise and set times.
\cos H_0 = -\tan phi \tan delta
H_0 = hour angle at rise/set, phi = observer latitude, delta = lunar declination
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Frequently Asked Questions
How do I calculate moonrise and moonset?
Enter your latitude, longitude, and the date to get the exact moonrise and moonset times for your location.
What factors affect moonrise and moonset times?
The Moon's declination, your geographic location (latitude and longitude), and local time-zone offset all influence these times.
Why do moonrise and moonset times change each day?
Due to the Moon's orbit around Earth and Earth's rotation, these times vary daily.
How does atmospheric refraction affect moonrise and moonset?
Atmospheric refraction causes the Moon to appear higher in the sky than it actually is, shifting observed moonrise and moonset times slightly.
Can I use this calculator for any location on Earth?
Yes, as long as you provide accurate latitude and longitude coordinates for your desired location.
What is the Moon's inclination to the ecliptic?
The Moon's orbit is inclined about 5° to the ecliptic plane, which affects its apparent path in the sky.
How do I adjust for daylight saving time when using this calculator?
Ensure your local time-zone offset accounts for any daylight saving time changes to get accurate moonrise and moonset times.
Results are for informational purposes only and do not constitute professional advice.