{
  "name": "Calibration card: daylight hours by latitude",
  "desc": "The values in the Calibration card at the top of the page, one field per row, with the source of each value.",
  "lic": "CC BY 4.0",
  "lic_url": "https://creativecommons.org/licenses/by/4.0/",
  "by": "The Yardstick Almanac",
  "url": "https://theyardstickalmanac.com/reading-charts/daylight-hours-by-latitude/",
  "from": [
    "Sunrise definition: U.S. Naval Observatory, Rise, Set, and Twilight Definitions (center of the Sun 50 arcminutes below the horizon)",
    "Solar-position equations from Meeus, as documented for the NOAA Global Monitoring Laboratory solar calculator",
    "JPL planetary ephemeris DE440 (de440s.bsp, unmodified), read with Skyfield 1.55"
  ],
  "how": "Compiled by The Yardstick Almanac from the data listed",
  "data_by": [
    "Daylight hours computed for 2026 from the USNO sunrise definition with the Meeus solar equations and the JPL DE440s ephemeris, 2026-11-01, CC BY 4.0"
  ]
}