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Moon Phases

Multiple moons with configurable cycle lengths, phases, and colors.


Configure moons via Calendar Editor > Moons tab:

SettingDescription
NameMoon display name
Cycle LengthDays for one complete cycle
ColorTint color for icon display
Reference DateA known new moon date (year, month, day)
Cycle Day AdjustFine-tune phase alignment
Reference PhaseWhich phase the moon is at on the reference date

Each phase can be customized with:

  • Name: Phase name (e.g., “Full Moon”)
  • Rising/Fading: Optional sub-phase names for multi-day phases
  • Icon: SVG path or emoji
  • Start/End: Cycle position (0-1)

An interactive phase slider in the Moons tab lets you adjust phase boundaries by dragging handles between segments. See Calendar Editor: Moon Phases for details.


Each moon has a Phase Mode setting that determines how its phase is calculated over time.

The moon follows a predictable, repeating cycle. The phase on any given day is determined by:

  1. Days since the reference date
  2. Position within the cycle (daysSinceReference % cycleLength)
  3. Which phase contains that position

Phases repeat at exact intervals, producing a regular, real-world-style lunar cycle.

The moon follows an erratic, non-cyclical pattern driven by seeded randomness. The base cycle length still influences overall pacing, but the actual phase on any day varies unpredictably. Good for alien, magical, or chaotic moons (e.g., Warhammer’s Morrslieb).

Randomized moons are configured with:

SettingDescription
SeedInteger seed for randomization. The same seed always produces the same sequence. Use the dice button to randomize
Cycle VarianceSlider (01) controlling how much the moon deviates from its base cycle length. At 0, the moon behaves identically to fixed mode. At 1, phases shift dramatically and unpredictably between days
Phase WeightPer-phase number (minimum 1) controlling how likely that phase is relative to the others. A phase with weight 2 occupies twice as much of the cycle as a phase with weight 1, making it twice as likely to appear

Same seed always produces the same results.

Anchor phases are date-specific phase overrides available in Randomized mode. They guarantee a moon is in a specific phase on a specific date, regardless of what the randomization would otherwise produce.

Configure anchor phases in Calendar Editor > Moons tab by clicking Add Anchor Phase. Each anchor defines:

FieldDescription
YearThe year to match. Leave blank for yearly recurrence (the anchor repeats every year)
MonthThe month the anchor falls on
DayThe day of the month
PhaseWhich phase the moon should display on the anchored date (selected from the moon’s phases)

For example, an anchor with no year, month “Hexenstag”, day 1, and phase “Full Moon” ensures the moon is always full on the first day of Hexenstag every year.


When a phase spans multiple days:

  • First third: “Rising [Phase]” (or custom rising name)
  • Middle third: Main phase name
  • Last third: “Fading [Phase]” (or custom fading name)

Moon phases display on calendar day cells when Show Moon Phases is enabled. Controlled per-application:

  • Settings Panel > MiniCal tab > Block Visibility > Show Moon Phases
  • Settings Panel > BigCal tab > Block Visibility > Show Moon Phases

BigCal: Shows moon icons for each configured moon, tinted with their colors. When there are many moons, a +X indicator appears to show how many additional moons exist beyond the displayed icons.

MiniCal: Shows a single moon icon due to space constraints. Click the moon icon to cycle through available moons when multiple are configured.

The HUD dome renders moons with phase-accurate shadows and color glow. With Show All Moons enabled (Settings > HUD tab), secondary moons trail behind the primary moon at a smaller size.


Moons reduce nighttime scene darkness based on their phase. Each moon has a Brightness Max slider (00.3, default 0) in Calendar Editor > Moons tab.

Illumination follows a cosine curve: maximum at full moon, zero at new moon. Multiple moons sum their values (capped at 0.3). Each moon’s light is tinted with its configured color.

Enable/disable via Settings Panel > Canvas tab > Moon Illumination.

See Scene Ambience: Moon Illumination for how this affects darkness calculations.


Notes repeat on specific moon phases. In the note editor:

  1. Set repeat pattern to Moon Phase
  2. Select which moon(s) to track
  3. Choose the phase range (e.g., Full Moon only, or a range like 0.5-0.625)
  4. Optionally select a modifier to target a specific portion of multi-day phases:
ModifierDescription
AnyAny time during the phase (default)
RisingFirst third of the phase
TrueMiddle third of the phase
FadingLast third of the phase

Modifiers align with the sub-phase display system (Rising/True/Fading). For example, “Full Moon (Rising)” triggers only during the first third of the Full Moon phase.

See Notes and Events for more on recurrence patterns.


See API Reference and Hooks.