Dictionary term
Greenwich Hour Angle
Direct answer
Greenwich Hour Angle is the angular distance measured westward from the Greenwich meridian to a body's hour circle.
Greenwich Hour Angle is a Greenwich-referenced celestial angle used in historical astronomy, timekeeping, or navigation.
Greenwich Hour Angle is a Greenwich-referenced celestial angle used in historical astronomy, timekeeping, or navigation.
An engraved functional orientation; the page explains the real instrument, method, or publication.Quick reference
- Use when
- Use Greenwich Hour Angle by interpolating the correct date and UTC entry and applying increments exactly as the almanac directs.
- Do not use it for
- Using the wrong civil date near midnight or confusing Aries GHA with a body value causes large errors.
- Reference category
- Historical Almanacs & Instruments
- Related terms
- Running Fix, Local Hour Angle, Assumed Position, Observed Altitude
The Chapter · Mystery School
Learn to read the sky for yourself
A mystery school of astrology with a worldwide chapter: letters on the chart and the soul, readings under one sky, and a rule of honesty about what the stars can and cannot say.
- The founding letter, with what the school studies and how it meets
- First word each season, when the doors open
- A seat at the gatherings, wherever in the world you are
Reading about Greenwich Hour Angle? The chapter is where readers like you meet.
Founding circle · forming now
The list costs nothing. Word of the school and its gatherings, nothing else. Unsubscribe at any time.
The story behind Greenwich Hour Angle
Greenwich hour angle became a compact standard coordinate in nautical almanacs and sight reduction.
Greenwich Hour Angle in spiritual tradition
Greenwich Hour Angle rewards careful observation, explicit assumptions, and humility about the limits of every model or measurement.
Greenwich Hour Angle: fact and faith, kept distinct
This is a factual history-of-science, instrument, timekeeping, or navigation reference. It may support wonder and disciplined attention without becoming a claim of fate, worship, or private revelation.
Greenwich Hour Angle in numerology
Greenwich Hour Angle 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 Greenwich Hour Angle matters
Greenwich Hour Angle matters because it supplies the almanac bridge between a body's celestial position and terrestrial longitude.
Greenwich Hour Angle at work: an example
A navigator looks up the Sun's hourly GHA and adds the minute-and-second increment for the sight time.
Where interpretation stops
Greenwich Hour Angle 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: Astronomical and Navigational Almanacs - Official descriptions of the Astronomical Almanac, Nautical Almanac, and their tabular data.
- 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
- Also appears in
- Historical Almanacs & Instruments
- Aliases
- None listed
- Last updated
- 2026-07-16
Explore Greenwich Hour Angle
Greenwich Hour Angle in a book is one thing; Greenwich Hour Angle 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
- Longitude by Chronometer
- Moon Sight
- Planet Sight
- Sector Instrument
- Transit Instrument
- Armillary Sphere
- Canon of Eclipses
- Davis Quadrant
Common questions
What is Greenwich Hour Angle?
Greenwich Hour Angle is the angular distance measured westward from the Greenwich meridian to a body's hour circle.
How is Greenwich Hour Angle used in an almanac?
Use Greenwich Hour Angle by interpolating the correct date and UTC entry and applying increments exactly as the almanac directs.
What should I avoid when interpreting Greenwich Hour Angle?
Using the wrong civil date near midnight or confusing Aries GHA with a body value causes large errors.
