ObjID137-1
‹ Ancient Sundials
Dialface ID 135
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Abstract
Gibbs: Damage at the top surface of the dial has destroyed the dimensions of the gnomon hole. [...] Rounded sides rising from a plinth base mark this dial as a member of a group of similarly shaped examples from the islands of Rhodes and Kos. […] Two parallel grooves decorate the lip. A trace of lead has been preserved in the square mount hole at the center of the bottom surface.
Measurements
Measurement record: pipeline ObjID 137, matched to this dialface by inventory number.
| Quality grade | B (completeness 88 %) |
|---|---|
| Dial surface | cone (decisive) · fit residual mm: cone 2.32, cylinder 3.77, sphere 5.35 |
| Latitude φ | 36.80 ± 0.99° (consensus of witnesses) |
| Klima | Delos, Rhodes (IV), Athens |
| Engraved lines | 10 hour lines, 3 day lines |
| Cone half-angle α | not shown: the derived cone does not agree with the measured points (residual 7.7 mm; verified cones give under 1 mm); under review |
| Measured | 2026-06-12 20:22 |
What the dial shows at this latitude
| Winter solstice | Equinox | Summer solstice | |
|---|---|---|---|
| Noon altitude of the Sun | 29.5° | 53.2° | 76.9° |
| Noon shadow (gnomon heights) | 1.77 | 0.75 | 0.23 |
| Length of the day | 9.4 h | 12.0 h | 14.6 h |
| Length of a seasonal hour | 47 min | 60 min | 73 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
- – Gibbs, Sharon L., Greek and Roman Sundials, New Haven and London, 1976, p. 254, p. 255, plate 35.
3D Models
