Anchoring cycles to real events

When you create a cycle, its anchor sets its alignment. The cycle defines its period and phases relative to the master timeline; the anchor tells PostRoll when the cycle was at which phase.

The most common workflow: you’ve got an event (a festival, a historical moment, a session) and you want a specific phase to fall on it. “I want a full moon on Lanternfall, year 1247 SR.”

The two anchor fields

Field	What it means
Anchor point	A master timeline position — the reference moment.
Phase index	Which phase the cycle sits at, at that moment.

Together they say “at master timeline position X, the cycle was at phase Y”. The cycle then fans out forward and backward from there using its period.

The recipe — anchoring a moon to a festival

1. Create the festival event if you haven’t already. Open the event in the Inspector and find its master timeline position — the small number shown at the bottom of the When section. Copy that number — it’s the moment your festival happens.

2. Pick the phase index you want at that moment. For the Standard Moon template, the ordinals are:

   Phase	Ordinal
   New Moon	0
   Waxing Crescent	1
   First Quarter	2
   Waxing Gibbous	3
   Full Moon	4
   Waning Gibbous	5
   Last Quarter	6
   Waning Crescent	7

   For a full moon, that’s 4.

3. Open Settings → Cycles → your moon cycle.

4. Set the anchor point to the number you copied.

5. Set the phase index to 4 (or whatever phase you want).

6. Save. The cycle now reads “Full” at that festival’s moment.

What this does to other dates

The cycle’s period is unchanged, so:

• 14 days before the anchor → New Moon (phase 0).
• 7 days before the anchor → Last Quarter (phase 6).
• 7 days after the anchor → First Quarter (phase 2).
• 14 days after the anchor → New Moon again.

The Cycles dashboard’s “Now” reading and the Calendar tab’s phase chips immediately reflect the new anchor — every view recalculates on the fly, with nothing to update by hand.

Re-anchoring later

Anchors aren’t sticky to that one event. They’re just a reference point. If you decide later that the moon should be Waxing Gibbous on Lanternfall (not Full), open the cycle, change the phase index, save. Every chip in every view updates.

Anchoring tides to noon

A simple one. If you want low tide at noon and high tide at midnight:

• Anchor point — the master timeline position for noon on the day you’re anchoring to. For 2026-05-05 noon, that’s master timeline position 29110320.
• Phase index — 0 (Low Tide).

Tides will run roughly 12 hours apart from there. If your in-world day length differs from 24 hours, set the cycle’s period to half your in-world day’s length in minutes (for a twice-daily tide).

Anchoring seasons

Seasons usually anchor to a calendar’s New Year:

• Find the master timeline position for Year 1 Day 1 of your primary calendar by opening the Inspector for any year-1 event and copying its position.
• Set the cycle’s anchor point to that.
• Set the phase index to 0 (Winter / first season) — or whichever season your year starts in.

Seasons rotate through the year; the calendar’s January-to-December months will line up with the four ~91-day phases.

Tip

You don’t need to be exact. Cycles are inherently periodic — if you anchor a moon “approximately” right, every fortnight feels right soon enough. The Calendar phase chips and Cycles dashboard make errors visible quickly; iterate.

Multi-moon de-synchronisation

For settings with multiple moons (Selûne and Shar in Forgotten Realms; the three moons of Eberron), clone the Standard Moon template once per moon and set their anchor points to different values so they’re not in sync. A common pattern:

• First moon — anchor at master timeline position X, phase 0.
• Second moon — anchor at position X + (period ÷ 4), phase 0 → second moon is 1/4 of a cycle ahead of the first.
• Third moon — anchor at position X + (period ÷ 2), phase 0 → third moon is 1/2 of a cycle ahead.

Now the Calendar day chips show three different phase emojis per day — visually rich without your having to compute phases manually.

Related

• Building a cycle
• Cycle templates
• The Cycles tab — verify your anchor with the date scrubber