moon-cycle/.github/wiki/api/functions/cycleYear.md

moon-cycle v2.0.0

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moon-cycle / cycleYear

Function: cycleYear()

cycleYear(date?): string

Defined in: cycleYear.ts:17

Maps a date to the corresponding NASA moon image for the yearly cycle.

The yearly dataset contains 8,760 hourly images covering the full calendar year 2023 (365 days × 24 hours). This function computes the fractional position within a 365-day year relative to 2023-01-01 and maps that fraction to an image index in [1, 8760].

The cycle repeats annually, so dates in any year resolve to the equivalent hour-of-year position in the 2023 imagery.

Parameters

date?

Date = ...

The date to resolve. Defaults to the current time.

Returns

string

A zero-padded filename string, e.g. "4380.webp".