ObjID36-1
‹ Ancient Sundials
Dialface ID 35
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Abstract
This sundial's design is simple and unardorned. Gibbs: A gnomon hole, 30 mm in diameter, is visible in the top surface of the dial.
Measurements
Measurement record: pipeline ObjID 36, matched to this dialface by inventory number.
| Quality grade | B (completeness 100 %) |
|---|---|
| Dial surface | sphere (decisive) · fit residual mm: cone 5.32, cylinder 5.83, sphere 1.75 |
| Latitude φ | 38.50 ± 4.00° (consensus of witnesses) |
| Klima | Athens, Delos, Rhodes (IV) |
| Engraved lines | 11 hour lines, 3 day lines |
| Cone half-angle α | not shown: surface fit decisively sphere: cone-specific quantities do not apply |
| Measured | 2026-06-12 20:44 |
What the dial shows at this latitude
| Winter solstice | Equinox | Summer solstice | |
|---|---|---|---|
| Noon altitude of the Sun | 27.8° | 51.5° | 75.2° |
| Noon shadow (gnomon heights) | 1.90 | 0.80 | 0.26 |
| Length of the day | 9.3 h | 12.0 h | 14.7 h |
| Length of a seasonal hour | 46 min | 60 min | 74 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
- – Antonini, Carlo, Candelabri e orologgi solari antichi, Rome, 1790, no. 4.
- – Gibbs, Sharon L., Greek and Roman Sundials, New Haven and London, 1976, p. 150, p. 151.
- – Portaluppi, Piero, Gnomonica atellana : le meridiane dell'arte, l'arte delle meridiane, Milan, 1967, p. 19.
- – Zuzzeri, Luca Giovanni, Dissertazione d'un Antico Orologio a Sole, Venice, 1746, p. 62ff., pl. 1.
3D Models
