Old instruments
Mariner's Astrolabe
Direct answer
Mariner's Astrolabe is a robust open-frame astrolabe used at sea to measure the altitude of the Sun or a star.
Mariner's Astrolabe is a heavy marine altitude instrument used in historical astronomy, timekeeping, or navigation.
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At a glance
- Found in
- Historical Almanacs & Instruments
- Related
- Reflecting Circle, Hadley Quadrant, Equinoctial Ring Dial, Gunter's Quadrant
Mariner's Astrolabe is a heavy marine altitude instrument used in historical astronomy, timekeeping, or navigation.
An engraved functional orientation; the page explains the real instrument, method, or publication.
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The story behind Mariner's Astrolabe
Mariners used this simplified metal form especially during early oceanic navigation.
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Why Mariner's Astrolabe matters
Mariner's Astrolabe matters because its weighted, wind-resistant form adapted astrolabe geometry to a moving maritime environment.
Mariner's Astrolabe in practice: an example
A noon solar altitude could be combined with declination to estimate latitude.
Where readings of Mariner's Astrolabe go wrong
Ship motion, wind, coarse graduations, and direct solar sighting limited accuracy and safety.
Sources and editorial method
Research references used for this entry include:
- Royal Museums Greenwich: Astronomical and Navigational Instruments - Museum reference collection for historical observing, calculating, timekeeping, and navigation instruments.
- Source
- The Great Almanac Dictionary
- Category
- Historical Almanacs & Instruments
- Last updated
- 2026-09-26
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More in Historical Almanacs & Instruments
- Octant
- Refraction Correction
- Star Sight
- Alidade
- Astronomical Ephemeris Table
- Clepsydra
- Equatorial Telescope
- Latitude by Meridian Altitude
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Common questions
What is Mariner's Astrolabe?
Mariner's Astrolabe is a robust open-frame astrolabe used at sea to measure the altitude of the Sun or a star.
What do people get wrong about Mariner's Astrolabe?
Ship motion, wind, coarse graduations, and direct solar sighting limited accuracy and safety.
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