Dictionary term
Moonset
Direct answer
Moonset is the calculated instant when the Moon's upper limb disappears below the observer's horizon under standard rise-and-set assumptions.
Moonset is the local horizon time when the Moon finishes setting.
Moonset is the local horizon time when the Moon finishes setting.
A Sun–Earth orientation for seasonal, atmospheric, tidal, and terrestrial terms.Quick reference
- Use when
- Use Moonset with local coordinates, phase, date, and time zone, especially when planning meteor or deep-sky observation.
- Do not use it for
- Do not treat a geometric set time as exact for an obstructed horizon.
- Reference category
- Seasons & Earth Almanac
- Related terms
- Astronomical Season, Meteorological Season, Equinox, Solstice
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The story behind Moonset
Moonset tables became a routine part of astronomical and navigational almanacs because the event depends on lunar motion and observer location.
Moonset in spiritual tradition
Moonset reminds the observer that darkness itself has changing local conditions.
Moonset: fact and faith, kept distinct
This is a factual astronomy, calendar, Earth-science, cultural, or historical reference. It can support wonder at the created order without becoming a claim of fate, worship, or private revelation.
Moonset in numerology
Moonset is not a numerology claim. Any numbers attached to it should retain their ordinary scientific, calendrical, navigational, or historical meaning unless a separate symbolic interpretation is clearly labeled.
Why Moonset matters
Moonset determines dark-sky windows and explains whether Moon light will interfere with evening or predawn observing.
Moonset at work: an example
Observers may wait until after a bright Moon sets to see fainter meteors or the Milky Way.
Where interpretation stops
Moonset is presented as sourced astronomy, calendrical, Earth-science, cultural, or instrument-history reference. Definitions should distinguish measured phenomena from civil convention and historical interpretation, preserve location and time dependencies, and avoid turning factual sky data into a deterministic personal claim.
Sources and editorial method
Research references used for this entry include:
- U.S. Naval Observatory: Rise, Set, and Twilight Definitions - Definitions used by USNO for sunrise, sunset, moonrise, moonset, and twilight.
- U.S. Naval Observatory: Complete Sun and Moon Data - Authoritative astronomical data services for positions, phases, and rise and set events.
- Source
- The Great Almanac Dictionary
- Category
- Seasons & Earth Almanac
- Also appears in
- Seasons & Earth Almanac
- Aliases
- None listed
- Last updated
- 2026-07-15
Find the Moon-free window
Moonset in a book is one thing; Moonset in your own birth chart is your life. The Oracle casts your real chart and tells you what it means for your love, your work, and your year ahead, in conversation, free.
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More in Seasons & Earth Almanac
- Photoperiod
- Solar Declination
- Amphidromic Point
- Brocken Spectre
- Dawn
- Equinoctial Tide
- Horizon Refraction
Common questions
What is Moonset?
Moonset is the calculated instant when the Moon's upper limb disappears below the observer's horizon under standard rise-and-set assumptions.
How is Moonset used in an almanac?
Use Moonset with local coordinates, phase, date, and time zone, especially when planning meteor or deep-sky observation.
What should I avoid when interpreting Moonset?
Do not treat a geometric set time as exact for an obstructed horizon.
