ObjID28-1
‹ Ancient Sundials
Dialface ID 28
Page 1 of 2
Abstract
This sundial has no ornaments in relief. Its frontLP and base are broken away, therefore the original ratio is undistinguishable. The hourlines and two daycurves were filled with red colour. Gibbs: The original gnomon hole has been filled by a restorer, and a thin wire gnomon has been inserted.
Measurements
Measurement record: pipeline ObjID 28, matched to this dialface by inventory number.
| Quality grade | A (completeness 82 %) |
|---|---|
| Dial surface | cone (decisive) · fit residual mm: cone 1.45, cylinder 15.20, sphere 3.82 |
| Latitude φ | 13.26 ± 0.59° (consensus of witnesses) |
| Klima | nearest Meroe (5.4 sigma) |
| Engraved lines | 11 hour lines, 2 day lines |
| Cone half-angle α | not shown: the derived cone does not agree with the measured points (residual 7.2 mm; verified cones give under 1 mm); under review |
| Measured | 2026-06-12 20:39 |
What the dial shows at this latitude
| Winter solstice | Equinox | Summer solstice | |
|---|---|---|---|
| Noon altitude of the Sun | 53.0° | 76.7° | 79.5° |
| Noon shadow (gnomon heights) | 0.75 | 0.24 | 0.18 |
| Length of the day | 11.2 h | 12.0 h | 12.8 h |
| Length of a seasonal hour | 56 min | 60 min | 64 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. 143, p. 144, plate 6.
3D Models
