Dictionary term
Nautical Dusk
Direct answer
Nautical Dusk is the evening instant when the Sun center reaches 12 degrees below the horizon.
Nautical Dusk ends nautical twilight at a -12-degree solar altitude.
Nautical Dusk ends nautical twilight at a -12-degree solar altitude.
A Sun–Earth orientation for seasonal, atmospheric, tidal, and terrestrial terms.Quick reference
- Use when
- Use Nautical Dusk for marine observing, twilight photography, and the transition into darker sky.
- Do not use it for
- Local haze and sea state can erase the horizon well before the calculated threshold.
- Reference category
- Seasons & Earth Almanac
- Related terms
- Nautical Dawn, Astronomical Dawn, Astronomical Season, Equinox
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The story behind Nautical Dusk
Sextant practice made evening nautical twilight a valuable period for obtaining multiple star sights.
Nautical Dusk in spiritual tradition
Spiritually, Nautical Dusk can honor the skill of navigating by evidence in diminishing light.
Nautical Dusk: 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 Dusk in numerology
Nautical Dusk 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 Dusk matters
It marks the end of the classic evening period when horizon and navigational stars may both be discernible.
Nautical Dusk at work: an example
After Nautical Dusk, the horizon usually becomes harder to distinguish even as more stars emerge.
Where interpretation stops
Nautical Dusk 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 evening navigation window
Nautical Dusk in a book is one thing; Nautical Dusk 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 Dusk?
Nautical Dusk is the evening instant when the Sun center reaches 12 degrees below the horizon.
How is Nautical Dusk used in an almanac?
Use Nautical Dusk for marine observing, twilight photography, and the transition into darker sky.
What should I avoid when interpreting Nautical Dusk?
Local haze and sea state can erase the horizon well before the calculated threshold.
