Lunar Structure

Lunar Structure (M0–M13)

The Light Calendar includes a simple lunar index. Each lunar cycle is assigned to the year in which its full moon occurs.

Occasionally, a lunar cycle begins in the previous year and its *full moon falls before the Solar New Year. This case is labelled M0.

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Rules

• Lunar numbering: M0–M13
  • M0 appears only when a lunar cycle starts in the previous Gregorian year
    but belongs to the new Light Year because its full moon occurs before 1 New February.
  • Normal cycles start at M1.
• A lunar cycle begins at the astronomical new moon, rounded using a natural rule:
  • New moon before 12:00 UTC → previous night
  • New moon at/after 12:00 UTC → same day
• Cycle length is 29 or 30 days.
• Users see the moon day (1–30) in their own local timezone.

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Example Notation

Μ11·19(16/30)

Meaning:

• Μ11 → 11th moon of the Light Year
• 19 → today is day 19 of this lunar cycle
• 16 → the full moon occurred on day 16
• 30 → total length of this cycle

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Why M0 Exists

M0 ensures:

• lunar cycles are not cut by the Light Year boundary,
• each moon is consistently assigned to exactly one Light Year,
• astronomy and calendar logic stay aligned.

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Purpose

The lunar index (M1–M13, sometimes M0) provides full lunar orientation without a separate lunar calendar, while staying astronomically precise.