Dictionary term
Hour Angle
Direct answer
Hour Angle measures westward angular distance from the local meridian to an object’s hour circle.
It tells how far an object is from meridian transit.
It tells how far an object is from meridian transit.
A scientific orientation to scale, light, or motion; the article supplies the precise definition.Quick reference
- Use when
- Use signed or wrapped values consistently and state the convention.
- Do not use it for
- Hour angle is angular time, not the duration an object has been visible.
- Reference category
- Astronomy & Skywatching
- Related terms
- Celestial Meridian, Local Meridian, Position Angle, Angular Separation
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The story behind Hour Angle
Hour angle was fundamental to transit instruments and equatorial mounts.
Hour Angle: fact and faith, kept distinct
This is a factual astronomy reference. It can support wonder at the created order without becoming a claim of fate, worship, or private revelation.
Hour Angle in numerology
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 Hour Angle matters
It links right ascension, local sidereal time, and telescope tracking.
Where interpretation stops
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 Almanac Glossary - Definitions for astronomical coordinates, time, reference systems, and observable phenomena.
- International Astronomical Union: Standards of Fundamental Astronomy - IAU-maintained standards and algorithms for astronomical reference systems and coordinate transformations.
- Source
- The Great Almanac Dictionary
- Category
- Astronomy & Skywatching
- Also appears in
- Astronomy & Skywatching
- Aliases
- None listed
- Last updated
- 2026-07-16
Calculate time from the meridian
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More in Astronomy & Skywatching
- Naked-Eye Astronomy
- Planetary Magnetosphere
- Reflection Nebula
- South Celestial Pole
- Two-Body Problem
- Ascending Orbital Node
- Celestial Equator
- Equatorial Coordinate System
Common questions
What is Hour Angle?
Hour Angle measures westward angular distance from the local meridian to an object’s hour circle.
How is Hour Angle used in an almanac?
Use signed or wrapped values consistently and state the convention.
What should I avoid when interpreting Hour Angle?
Hour angle is angular time, not the duration an object has been visible.
