5678910111213141516171819the sun at the instant1° up

Since Eratosthenes, the Tropic of Cancer has crept 32 km toward the equator

· 05:01 on 21 June at Kirihata-ji

A pilgrim’s staff at Kirihata-ji, Temple 10 of the Shikoku 88, one temple per turning. Its strokes are its shadow hour by hour through 21 June by the temple’s clock, the red one at the instant; the dotted line follows the shadow’s tip.

Temple 10 of 88next, Fujii-deraon 22 September 2028

Summer Solstice 2028

the longest light — 20 June, 20:01 UTC

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How this is computed

The sun's position uses the NOAA Solar Calculator's equations — declination within 0.004°, the equation of time within 4 seconds, against JPL Horizons for 2000–2050. The moon and the deep-time scrubber use Meeus, Astronomical Algorithms (2nd ed.). Ancient solar and lunar alignments are pinned from archaeological literature (Ruggles, Astronomy in Prehistoric Britain and Ireland), not derived from the model. Good for contemplation, not for navigation. The deep-time horizon uses each year's obliquity (valid roughly 3000 BC–3000 AD) for the sunrise/sunset azimuth, against a fixed alignment bearing: Stonehenge's solstitial axis (Lockyer & Penrose 1901; Ruggles 1997) and the great-circle bearing from Ōmori-Katsuyama to Mt. Iwaki's summit, whose winter-solstice sunset is documented by Kaner (World Archaeology 115, 2022) and the UNESCO Jōmon listing. Azimuths assume a flat sea-level horizon and ignore atmospheric refraction (~0.5°) and disc radius, so they mark the geometric event, not the first gleam.

The plate's staff walks the 88 temples of the Shikoku pilgrimage, one temple per turning, and its sun is the same NOAA series, at the temple. Contains information from Open Pilgrimages, made available under the ODbL. Route data © OpenStreetMap contributors. The place under the sun is named from GeoNames (CC BY 4.0) and measured to Natural Earth's coastlines (public domain). The strip's colours are the daily sky photos at ig.fz.ax (CC0); a photo's time is read as the same clock hour at the temple, never as the same sun.