ObjID155-1
‹ Ancient Sundials
Dialface ID 154
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Abstract
A portion of bronze gnomon remains in position in the top of the dial above the meridian. Eleven hour lines radiate from the gnomon to the lower edge of the conical surface. Two day curves, always equidistant from the lower edge. Two four-toed griffon feet decorate the base. Honey-suckle vines and flowers decorate the center of the base and the left and right sides.
Measurements
Measurement record: pipeline ObjID 155, matched to this dialface by inventory number.
| Quality grade | A (completeness 55 %) |
|---|---|
| Dial surface | cone (preferred, not decisive) · fit residual mm: cone 0.41, cylinder 0.56, sphere 3.20 |
| Latitude φ | 37.22 ± 0.67° (single witness: path-III-front-back) |
| Engraved lines | 11 hour lines, 2 day lines |
| Cone half-angle α | 6.5 ± 0.19° (cone residual on all points 0.41 mm) |
| Measured | 2026-06-12 21:23 |
What the dial shows at this latitude
| Winter solstice | Equinox | Summer solstice | |
|---|---|---|---|
| Noon altitude of the Sun | 29.1° | 52.8° | 76.5° |
| Noon shadow (gnomon heights) | 1.80 | 0.76 | 0.24 |
| 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
- – Ardaillon, Édouard, Horologium, Paris, 1877-1919, p. 257, figure 3884 (drawing).
- – Gibbs, Sharon L., Greek and Roman Sundials, New Haven and London, 1976, p. 272, p. 273, plate 39.
3D Models
