ObjID513-1
‹ Ancient Sundials
Dialface ID 556
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Abstract
Information on the Dialface ID 556 / Object ID 513
Measurements
Measurement record: pipeline ObjID 513, matched to this dialface by inventory number.
| Quality grade | B (completeness 88 %) |
|---|---|
| Dial surface | cone (decisive) · fit residual mm: cone 0.30, cylinder 3.77, sphere 6.60 |
| Latitude φ | 38.47 ± 1.94° (consensus of witnesses) |
| Klima | Athens, Delos, Rhodes (IV) |
| Engraved lines | 10 hour lines, 3 day lines |
| Cone half-angle α | 36.0 ± 0.05° (cone residual on all points 0.34 mm) |
| Measured | 2026-06-12 20:55 |
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
3D Models
