Dictionary term
Astronomical Dusk
Direct answer
Astronomical Dusk is the evening instant when the Sun center descends to 18 degrees below the horizon.
Astronomical Dusk ends astronomical twilight at a -18-degree solar altitude.
- Source
- The Great Almanac Dictionary
- Category
- Seasons & Earth Almanac
- Also appears in
- Seasons & Earth Almanac
- Aliases
- None listed
- Last updated
- 2026-07-16
Quick reference
- Use when
- Use Astronomical Dusk to plan dark-sky imaging, faint-object observing, and nightly almanac windows.
- Do not use it for
- Do not assume the sky will be dark at the threshold when Moon, aurora, smoke, or artificial light is present.
- Reference category
- Seasons & Earth Almanac
- Related terms
- Astronomical Dawn, Inferior Mirage, Astronomical Season, Equinox
The story behind Astronomical Dusk
Observatory schedules adopted the standard as a practical approximation for when scattered sunlight becomes negligible.
Astronomical Dusk in spiritual tradition
Spiritually, Astronomical Dusk can open a period of attentive night observation grounded in actual sky conditions.
The Great Almanac frames Astronomical Dusk with educational restraint. Mystical or symbolic language may be meaningful, but it should not be exaggerated into certainty, panic, or permission to ignore ordinary responsibility.
Astronomical Dusk in the Bible
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.
Astronomical Dusk in numerology
Astronomical 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 Astronomical Dusk matters
It marks the conventional beginning of full natural night for many astronomical observations.
Example in a reading: At high summer latitudes Astronomical Dusk may not occur, leaving no formally defined astronomical night.
Interpretive caution: Do not assume the sky will be dark at the threshold when Moon, aurora, smoke, or artificial light is present.
How Astronomical Dusk is used in a reading
Use Astronomical Dusk to plan dark-sky imaging, faint-object observing, and nightly almanac windows.
Where interpretation stops
Astronomical 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.
The page starts with a direct definition, then separates use, example, caution, spiritual meaning, and historical context. For astrology, occult, demonology, curse, and spiritual warfare terms, the editorial rule is to explain the term without making fear-based, fatalistic, medical, legal, financial, or ritual-instruction claims.
Continue learning
Continue into the live sky, space weather, universal timing, and the wider field surrounding the current season.
Open Worldwide WatchRelated terms
These related entries help place Astronomical Dusk inside a wider reference cluster instead of leaving it as a standalone keyword.
