Dictionary term
Nautical Twilight
Direct answer
Nautical Twilight is the interval when the Sun center lies between 6 and 12 degrees below the horizon.
Nautical Twilight spans Sun altitudes from -6 to -12 degrees.
Nautical Twilight spans Sun altitudes from -6 to -12 degrees.
A Sun–Earth orientation for seasonal, atmospheric, tidal, and terrestrial terms.Quick reference
- Use when
- Use Nautical Twilight for navigation planning, marine operations, and observing the transition from bright to dark sky.
- Do not use it for
- Do not assume the sea horizon or stars will be visible through fog, cloud, glare, or heavy light pollution.
- Reference category
- Seasons & Earth Almanac
- Related terms
- Civil Twilight, Blue Hour, Astronomical Season, Equinox
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The story behind Nautical Twilight
Mariners relied on the twilight overlap between a visible sea horizon and navigational stars for sextant sights.
Nautical Twilight in spiritual tradition
Spiritually, Nautical Twilight recalls the disciplined observation that once guided travelers across open water.
Nautical Twilight: fact and faith, kept distinct
This is a factual calendar, astronomy, Earth-science, cultural-history, or observational reference. It can support wonder and practical planning without becoming a claim of fate, spiritual causation, or private revelation.
Nautical Twilight in numerology
Nautical Twilight 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 Nautical Twilight matters
During favorable conditions the horizon and brighter stars can both be visible, historically supporting celestial navigation.
Nautical Twilight at work: an example
Morning Nautical Twilight ends at civil dawn when the Sun rises past 6 degrees below the horizon.
Where interpretation stops
Nautical Twilight 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 - Official definitions used for sunrise, sunset, refraction, and twilight calculations.
- NOAA Global Monitoring Laboratory: Solar Calculator Glossary - NOAA definitions for solar geometry, atmospheric refraction, and civil, nautical, and astronomical twilight.
- Source
- The Great Almanac Dictionary
- Category
- Seasons & Earth Almanac
- Also appears in
- Seasons & Earth Almanac
- Aliases
- None listed
- Last updated
- 2026-07-16
Plan the navigation-light interval
Nautical Twilight in a book is one thing; Nautical Twilight 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
Common questions
What is Nautical Twilight?
Nautical Twilight is the interval when the Sun center lies between 6 and 12 degrees below the horizon.
How is Nautical Twilight used in an almanac?
Use Nautical Twilight for navigation planning, marine operations, and observing the transition from bright to dark sky.
What should I avoid when interpreting Nautical Twilight?
Do not assume the sea horizon or stars will be visible through fog, cloud, glare, or heavy light pollution.
