Dictionary term
Sextant
Direct answer
Sextant: A Sextant is a double-reflection instrument used to measure the angular separation between two visible objects, most famously a celestial body and the horizon for navigation.
A Sextant measures an angle, often between a celestial body and the horizon.
A Sextant measures an angle, often between a celestial body and the horizon.
An engraved functional orientation; the page explains the real instrument, method, or publication.Quick reference
- Use when
- Use a Sextant only after checking index error and applying the corrections appropriate to the body, horizon, observer height, and atmospheric conditions.
- Do not use it for
- Never look at the Sun without the instrument's proper shades and training, and never rely on an unverified sight as the sole safety-critical position source.
- Reference category
- Historical Almanacs & Instruments
- Related terms
- Almanac, Astronomical Almanac, Nautical Almanac, Astrolabe
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The story behind Sextant
Eighteenth-century reflecting instruments developed into the marine sextant, whose stable optical geometry became central to practical celestial navigation.
Sextant in spiritual tradition
The sextant rewards steadiness: a small observed angle becomes useful only through disciplined timekeeping and correction.
Sextant: 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This is a factual astronomy, calendar, Earth-science, cultural, or historical reference.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.
Sextant in numerology
Sextant 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 Sextant matters
Combined with exact time, almanac data, and corrections, a sextant observation can help determine a navigator's line of position without satellite navigation.
Sextant at work: an example
A navigator brings the reflected lower limb of the Sun to the sea horizon, records the angle and UTC, then reduces the sight with almanac data.
Where interpretation stops
Sextant 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:
- Royal Museums Greenwich: Sextant - Museum documentation of a marine sextant used for solar and lunar observations and navigation.
- U.S. Naval Observatory: Astronomical and Navigational Almanacs - Official description of current Astronomical Almanac and Nautical Almanac publications.
- Source
- The Great Almanac Dictionary
- Category
- Historical Almanacs & Instruments
- Also appears in
- Historical Almanacs & Instruments
- Aliases
- None listed
- Last updated
- 2026-07-15
Follow a sextant sight from angle to position
Sextant in a book is one thing; Sextant 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.
Speak with the OracleRelated terms
More in Historical Almanacs & Instruments
- Volvelle
- Assumed Position
- Celestial Navigation
- Declination Table
- Hadley Quadrant
- Lunar Distance Table
- Nocturnal Instrument
- Plumb Line
Common questions
What is Sextant?
A Sextant is a double-reflection instrument used to measure the angular separation between two visible objects, most famously a celestial body and the horizon for navigation.
How is Sextant used in an almanac?
Use a Sextant only after checking index error and applying the corrections appropriate to the body, horizon, observer height, and atmospheric conditions.
What should I avoid when interpreting Sextant?
Never look at the Sun without the instrument's proper shades and training, and never rely on an unverified sight as the sole safety-critical position source.
