Dictionary term
Sidereal Month
Direct answer
Sidereal Month: A Sidereal Month is the time the Moon takes to return to the same direction relative to the stars.
A Sidereal Month measures the Moon orbit against a stellar reference.
A Sidereal Month measures the Moon orbit against a stellar reference.
A cycle or timeline schematic for comparing the named timekeeping concept.Quick reference
- Use when
- Use Sidereal Month in lunar position calculations and comparisons among lunar periods.
- Do not use it for
- Do not use the sidereal month to predict the next identical lunar phase.
- Reference category
- Calendars & Timekeeping
- Related terms
- Synodic Month, Anomalistic Month, Calendar, Julian Date
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 Sidereal Month? 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 Sidereal Month
Star-based observation provided a stable way to recognize the Moon orbital return independently of phase.
Sidereal Month in spiritual tradition
Spiritually, the sidereal month shows how one motion can produce different cycles against different backgrounds.
Sidereal Month: fact and faith, kept distinct
This is a factual calendar, astronomy, Earth-science, cultural-history, or observational reference. It can support wonder and practical planning without becoming a claim of fate, spiritual causation, or private revelation.
Sidereal Month in numerology
Sidereal Month 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 Sidereal Month matters
It distinguishes the Moon orbital revolution from its longer phase cycle, during which Earth also moves around the Sun.
Sidereal Month at work: an example
The mean sidereal month is about 27.32 days, roughly two days shorter than a synodic month.
Where interpretation stops
Sidereal Month 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 - Reference definitions for astronomical periods, coordinates, dates, and time scales.
- Source
- The Great Almanac Dictionary
- Category
- Calendars & Timekeeping
- Also appears in
- Calendars & Timekeeping
- Aliases
- None listed
- Last updated
- 2026-07-16
Compare orbital and phase months
Sidereal Month in a book is one thing; Sidereal Month 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 Calendars & Timekeeping
- Tropical Year
- Anomalistic Year
- Calendar Month
- Dominical Letter
- Era
- Intercalary Month
- Leap Year
- New Style Date
Common questions
What is Sidereal Month?
A Sidereal Month is the time the Moon takes to return to the same direction relative to the stars.
How is Sidereal Month used in an almanac?
Use Sidereal Month in lunar position calculations and comparisons among lunar periods.
What should I avoid when interpreting Sidereal Month?
Do not use the sidereal month to predict the next identical lunar phase.
