ObjID138-1
‹ Ancient Sundials
Dialface ID 136
Page 1 of 2
Abstract
The half bowl shape of the dial face rises from a square plinth with a mounting hole drilled into its bottom. Gibbs: A rectangular gnomon hole 42 mm long, 33 mm wide, and 18 mm deep, containing no metal residue, is preserved in the top of the dial. The general shape of the dial is characterized by rounded sides rising from a plinth base containing a round mount hole (diameter: 45 mm) in the bottom surface.
Measurements
Measurement record: pipeline ObjID 138, matched to this dialface by inventory number.
| Quality grade | B (completeness 89 %) |
|---|---|
| Dial surface | cone (decisive) · fit residual mm: cone 0.36, cylinder 7.12, sphere 8.22 |
| Latitude φ | 38.17 ± 0.91° (consensus of witnesses) |
| Klima | Athens, Delos |
| Engraved lines | 11 hour lines, 3 day lines |
| Cone half-angle α | 41.3 ± 0.61° (cone residual on all points 0.4 mm) |
| Measured | 2026-06-12 20:22 |
What the dial shows at this latitude
| Winter solstice | Equinox | Summer solstice | |
|---|---|---|---|
| Noon altitude of the Sun | 28.1° | 51.8° | 75.5° |
| Noon shadow (gnomon heights) | 1.87 | 0.79 | 0.26 |
| Length of the day | 9.3 h | 12.0 h | 14.7 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. 256.
3D Models
