ObjID438-1
‹ Ancient Sundials
Dialface ID 477
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Abstract
Information on the Dialface ID 477 / Object ID 438
Measurements
Measurement record: pipeline ObjID 438, matched to this dialface by inventory number.
| Quality grade | B (completeness 94 %) |
|---|---|
| Dial surface | cone (decisive) · fit residual mm: cone 1.09, cylinder 3.27, sphere 5.31 |
| Latitude φ | 64.30 ± 0.42° (single witness: hours-SuSo-regression) |
| Engraved lines | 7 hour lines, 3 day lines |
| Cone half-angle α | not shown: the derived cone does not agree with the measured points (residual 2.6 mm; verified cones give under 1 mm); under review |
| Measured | 2026-06-12 20:46 |
What the dial shows at this latitude
| Winter solstice | Equinox | Summer solstice | |
|---|---|---|---|
| Noon altitude of the Sun | 2.0° | 25.7° | 49.4° |
| Noon shadow (gnomon heights) | 28.82 | 2.08 | 0.86 |
| Length of the day | 3.2 h | 12.0 h | 20.8 h |
| Length of a seasonal hour | 16 min | 60 min | 104 min |
Computed for the measured latitude with the obliquity of the JPL ephemeris at 101 BC (year -100). The latitude is the one the dial was made for, not a find-spot coordinate.
References
- – D'Amore, Luigi, Allroggen-Bedel, Agnes, Barbet, Alix, Blanc, Nicole, Pisapia, Maria Stella, Miniero, Paola, Premier rapport sur l'étude de la Villa San Marco à Stabies, 1983, tav. 1, fig. 16.
3D Models
