ObjID23-1
‹ Ancient Sundials
Dialface ID 23
Page 1 of 3
Abstract
The FrontUP of this sundial is decorated with a rosette on both sides and a lying crescent in the middle. The frontUP and LP are connected by a torus moulding. Hourline 3, 6 and 9 have been painted with red paint. Gibbs: A rectangular gnomon hole, 24 mm wide, lies in the narrow center of the top surface close to the top front edge.
Measurements
Measurement record: pipeline ObjID 23, matched to this dialface by inventory number.
This object is registered in the measurement database, but its own record holds no measured values; see the variants below.
Variant NotSelectedPoints
| Quality grade | B (completeness 88 %) |
|---|---|
| Dial surface | sphere (decisive) · fit residual mm: cone 6.32, cylinder 6.94, sphere 1.25 |
| Latitude φ | 39.09 ± 0.16° (consensus of witnesses) |
| Klima | nearest Athens (6.9 sigma) |
| Engraved lines | 11 hour lines, 3 day lines |
| Cone half-angle α | not shown: surface fit decisively sphere: cone-specific quantities do not apply |
| Measured | 2026-06-12 20:36 |
What the dial shows at this latitude
| Winter solstice | Equinox | Summer solstice | |
|---|---|---|---|
| Noon altitude of the Sun | 27.2° | 50.9° | 74.6° |
| Noon shadow (gnomon heights) | 1.95 | 0.81 | 0.28 |
| 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
- – Gibbs, Sharon L., Greek and Roman Sundials, New Haven and London, 1976, p. 138.
- – Mauri, Amedeo, Pompeii, Rome, 1970, p. 108.
- – Severino, Nicola, De Monumentis Gnomonicis apud graecos et romanos. Le meridiane greco-romane. La storia, il catalogo, gli articoli, Roccasecca, 2003, p. 15.
3D Models
