ObjID510-1
‹ Ancient Sundials
Dialface ID 553
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Abstract
Information on the Dialface ID 553 / Object ID 510
Measurements
Measurement record: pipeline ObjID 510, matched to this dialface by inventory number.
| Quality grade | B (completeness 85 %) |
|---|---|
| Dial surface | cone (decisive) · fit residual mm: cone 0.74, cylinder 19.46, sphere 6.96 |
| Latitude φ | 42.16 ± 1.94° (consensus of witnesses) |
| Klima | Rome, Massalia, Hellespont (V) |
| Engraved lines | 7 hour lines, 3 day lines |
| Cone half-angle α | 40.7 ± 0.18° (cone residual on all points 0.75 mm) |
| Measured | 2026-06-12 20:54 |
What the dial shows at this latitude
| Winter solstice | Equinox | Summer solstice | |
|---|---|---|---|
| Noon altitude of the Sun | 24.1° | 47.8° | 71.5° |
| Noon shadow (gnomon heights) | 2.23 | 0.91 | 0.33 |
| Length of the day | 8.9 h | 12.0 h | 15.1 h |
| Length of a seasonal hour | 44 min | 60 min | 76 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
