Old instruments
Chronometer
Direct answer
Chronometer is a clock designed and tested to maintain a stable rate under demanding conditions.
Chronometer is a precision portable timekeeper used in historical astronomy, timekeeping, or navigation.
$0 today, then $12/month after 7 days. Cancel anytime.
At a glance
- Found in
- Historical Almanacs & Instruments
- Related
- Repeating Circle, Artificial Horizon, Marine Chronometer, Astronomical Clock
Chronometer is a precision portable timekeeper used in historical astronomy, timekeeping, or navigation.
An engraved functional orientation; the page explains the real instrument, method, or publication.
What does your own chart say about you?
Choose love, work or purpose. Your reading is written from your chart. Your reading uses your own birth details.
Walk through Alex’s whole example first
The Road of AgesSee the turning points of your whole life, from your birth date
See your road's shape
Prefer to explore first?
The Road of AgesThe turning points of your whole life, from your own chart
Walk my road
Free, by email
Your daily Almanac letter
One short letter at 7 each morning: the day’s theme read for your own chart, and one thing to do with it.
The story behind Chronometer
The chronometer label became closely associated with precision observatory and marine timekeeping.
A one-minute story
The Book of the Sky
How people learned to read the sky, from Babylon to the day you were born.
Why Chronometer matters
Chronometer matters because accurate elapsed and reference time make longitude and many astronomical reductions possible.
Chronometer in practice: an example
A navigator carries chronometer error forward from the latest comparison to estimate Greenwich time at a sight.
Where readings of Chronometer go wrong
A precision label does not guarantee current accuracy; shock, temperature, aging, and an unknown rate can invalidate trust.
Sources and editorial method
Research references used for this entry include:
- Royal Museums Greenwich: A Unique History of Timekeeping - Museum overview of marine chronometers, astronomical regulators, and the development of precision timekeeping.
- National Geospatial-Intelligence Agency: The American Practical Navigator - Official modern reference for navigation principles, celestial observations, sight reduction, and navigational tables.
- Source
- The Great Almanac Dictionary
- Category
- Historical Almanacs & Instruments
- Last updated
- 2026-09-26
Explore Chronometer
A definition tells you what it is; your own birth chart tells you what it means for you. The Oracle casts your real chart and answers for your love, your work, and your year ahead, in conversation. It opens with the 7-day Seeker trial.
Speak with the OracleRelated terms
More in Historical Almanacs & Instruments
From the reference page to your own chart
Every word here
is in your own chart.
- A personal reading about love, work or purpose, written from your chart
- A practical next step to consider
- It opens with 7 days free, with the AI Oracle and daily guidance
$0 today, then $12/month after 7 days. Cancel anytime.
Common questions
What is chronometer?
Chronometer is a clock designed and tested to maintain a stable rate under demanding conditions.
What do people get wrong about chronometer?
A precision label does not guarantee current accuracy; shock, temperature, aging, and an unknown rate can invalidate trust.
Free, by email
The Almanac, in your inbox at 7
One short letter at 7 each morning: the day’s theme read for your own chart, and one thing to do with it.
