ObjID516-1
‹ Ancient Sundials
Dialface ID 561
Abstract
Information on the Dialface ID 561 / Object ID 516
Measurements
Measurement record: pipeline ObjID 516, matched to this dialface by inventory number.
| Quality grade | B (completeness 70 %) |
|---|---|
| Dial surface | cone (decisive) · fit residual mm: cone 0.69, cylinder 1.99, sphere 4.92 |
| Latitude φ | 31.17 ± 3.27° (consensus of witnesses) |
| Klima | Alexandria (III), Rhodes (IV), Delos |
| Engraved lines | 9 hour lines, 2 day lines |
| Cone half-angle α | 33.3 ± 0.26° (cone residual on all points 0.71 mm) |
| Measured | 2026-06-12 20:56 |
What the dial shows at this latitude
| Winter solstice | Equinox | Summer solstice | |
|---|---|---|---|
| Noon altitude of the Sun | 35.1° | 58.8° | 82.5° |
| Noon shadow (gnomon heights) | 1.42 | 0.60 | 0.13 |
| Length of the day | 9.9 h | 12.0 h | 14.1 h |
| Length of a seasonal hour | 50 min | 60 min | 70 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
