{
  "site": "Painted Moons, https://paintedmoons.vercel.app",
  "what": "Every source the sheet is computed from or checked against, with its licence and the date it was read.",
  "sources": [
    {
      "name": "Phases of the Moon, NASA Goddard Space Flight Center (Fred Espenak)",
      "credit": "Phase instants checked against the NASA GSFC Moon phase catalog (Fred Espenak)",
      "urls": [
        "https://eclipse.gsfc.nasa.gov/phase/phases1801.html",
        "https://eclipse.gsfc.nasa.gov/phase/phases1901.html",
        "https://eclipse.gsfc.nasa.gov/phase/phases2001.html"
      ],
      "retrieved": "2026-10-10",
      "licence": "Permission is freely granted to reproduce this data when accompanied by an acknowledgment.",
      "used_for": "The phase receipt: every new moon, first quarter, full moon and last quarter the engine computes from 1899 to 2100 is compared with the catalog's instant, to the minute. Vendored whole to /phases.json."
    },
    {
      "name": "Jean Meeus, Astronomical Algorithms, 2nd edition (Willmann-Bell, 1998)",
      "credit": "Lunar and solar positions after Jean Meeus, Astronomical Algorithms (2nd ed., 1998), as implemented in Painted Skies",
      "chapters": [
        "7 and 12 (Julian day and sidereal time)",
        "13 (the horizon frame)",
        "14 (the parallactic angle, 14.1)",
        "15 (the Moon's altitude at the horizon)",
        "21 to 23 (precession, nutation, aberration)",
        "25 (the Sun)",
        "47 (the Moon's position)",
        "48 (the lit fraction and the position angle of the bright limb)",
        "49 (the principal phases)"
      ],
      "implementation": "src/astro/ is copied read-only from the Painted Skies studio and credited here; src/moons/ is new. Delta T is Espenak and Meeus's polynomial set, as Painted Skies implements it.",
      "used_for": "Every disc and every phase instant on the sheet. Worked examples 48.a and 49.a are receipts in test/."
    },
    {
      "name": "JPL Horizons, Solar System Dynamics Group, NASA Jet Propulsion Laboratory",
      "url": "https://ssd.jpl.nasa.gov/api/horizons.api",
      "retrieved": "2026-10-09",
      "licence": "US Government work",
      "used_for": "Reference figures for the lit-fraction, bright-limb and parallactic-angle receipts (test/disc.test.ts, test/parallactic.test.ts), in place of The Astronomical Almanac's daily tables, which are print-only."
    },
    {
      "name": "IANA Time Zone Database, zone.tab",
      "url": "https://data.iana.org/time-zones/tzdb/zone.tab",
      "version": "2026e",
      "retrieved": "2026-10-10",
      "licence": "Public domain",
      "used_for": "The towns offered by name, each with its own zone. The clock itself is the zone database in the visitor's browser (Intl), and on the server, Node's copy."
    },
    {
      "name": "Python zoneinfo (the IANA database as Python ships it)",
      "used_for": "An independent check of the eight clock fixtures in test/zones.test.ts."
    },
    {
      "name": "Typefaces",
      "faces": [
        "Brygada 1918 (SIL Open Font License 1.1)",
        "Albert Sans (SIL Open Font License 1.1)",
        "Azeret Mono (SIL Open Font License 1.1)"
      ],
      "via": "@fontsource-variable packages, self-hosted; the print renderer reads the same files."
    },
    {
      "name": "The four room photographs",
      "used_for": "The walls the sheet is hung on, to scale. Generated images of bare walls over an 84 in sofa, inherited from the Painted Skies studio; no person or real home is shown."
    }
  ]
}