Note: this is the least serious research I have done (we neeed archaeological proofs…), but I love it and I’m still convinced that the idea of a Bronze-age natural sundial makes sense, it’s there under our eyes.
ALBA LONGA: THE “SUNLIT RIDGE ” STILL VISIBLE TODAY
Hypothesis on the location of Alba Longa on the western crater rim of the Albano Lake,
based upon the observed light belt cast there soon after sunrise.
(published in: “Archeologia w teorii i w praktyce”, Warszawa – Poland , 2000).
NOTA PRELIMINARE SULL’INTERPRETAZIONE DI ALBA LONGA
COME “DORSALE ILLUMINATA DAL SOLE”.
(published in: “Documenta Albana”, II serie n. 21 – 1999 – Museo Civico Albano, pp. 25-42).
According to tradition, Alba Longa is the Latin town, founded in the XIIth century BC, from where, four centuries later, originated the foundation of Rome. It was destroyed in the VIIth century BC. In classical literature it is said to stretch out along a ridge at the base of Mount Albano, the religious centre of the Latin people dedicated to Jupiter, associated with the modern Monte Cavo. Until today the location of Alba Longa has never been established with certainty.
In this publication, the hypothesis is forwarded that the well-marked light belt, cast at sunrise upon the western rim of the Albano crater, might explain the name of Alba Longa as “sunlit ridge” (“sunlit” for alba, white), and therefore eventually confirm its location there. This hypothesis is based first upon field observations and then upon the results of three-dimensional dynamic modelling of the landscape- and solar data of the area around the Vulcano Laziale, south-east of Rome.
Although the whole western rim of the Albano crater is involved in the observed light pattern, the present town of Castel Gandolfo is proposed as the central place of the phenomenon. The particular morphological features of the volcano allow potentially the sun’s yearly evolution and crucial dates to be well observable from the western rim of the Albano crater and from Monte Cavo.
In the model the solar data of 1000 BC were used, a proxy for the foundation date of Alba Longa. However, the small differences in the sun’s azimuth angles between the past and the present, as well as the practically unchanged morphology of the volcano, render the “sunlit ridge” and the shadow cast by the Mount Albano (the “natural sundial”), so well visible today as it must have been 3000 years ago.
THE NATURAL SUNDIAL DURING THE REST OF THE YEAR
In the other times of the year, i.e. the periods around the equinox, each about 2 months long (if we take into account transition periods) and with a slight shift towards the summer solstice, the natural sundial changes it’s form from a sunlit belt into the pointed shadow of Monte Cavo (Mount Albano), cast in the early morning over the western rim of the Albano lake.
Between halfway summer solstice and autumn equinox, the morning shadow cast by the Monte Cavo is moving slowly from left to right, i.e. from S to N (see sundial scheme).
Between autumn equinox and winter solstice, the morning shadow is moving still further from S to N, reaching the town of Marino.
THE VIEW FROM CASTEL GANDOLFO
During the equinox period the sun rises close to the top of the Mount Albano, when seen from Castel Gandolfo and the area to the west of it. In the same period, the full moon rises as well in that position. To be remarked that full moons always rise in the same position as the sun, considering that sun and moon are then opposite to each other. But only during the equinox period the sun and the full moon rise close to Mount Albano when seen from Castel Gandolfo.
See also the article on the Nemi lake.