ObjID507-1
‹ Ancient Sundials
Dialface ID 550
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Abstract
Information on the Dialface ID 550 / Object ID 507
Measurements
Measurement record: pipeline ObjID 507, matched to this dialface by inventory number.
| Quality grade | B (completeness 71 %) |
|---|---|
| Dial surface | cone (decisive) · fit residual mm: cone 0.45, cylinder 2.91, sphere 4.14 |
| Latitude φ | 39.02 ± 1.03° (consensus of witnesses) |
| Klima | Athens, Delos, Hellespont (V) |
| Engraved lines | 10 hour lines, 2 day lines |
| Cone half-angle α | 38.6 ± 0.31° (cone residual on all points 0.49 mm) |
| Measured | 2026-06-12 20:53 |
What the dial shows at this latitude
| Winter solstice | Equinox | Summer solstice | |
|---|---|---|---|
| Noon altitude of the Sun | 27.3° | 51.0° | 74.7° |
| Noon shadow (gnomon heights) | 1.94 | 0.81 | 0.27 |
| Length of the day | 9.2 h | 12.0 h | 14.8 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
