aerial view of "Alba Longa" during summer solstice

Digital model of the illumination of the Latium Volcano during summer solstice of the year 1000 BC, 4.45 am (the 3rd of July when applying the Gregorian calendar, 18 minutes from sunrise. Within the circle the centre of the light belt, cast upon Castel Gandolfo. Height exaggeration factor of the landscape 3.8x. Sun’s position indicated by symbol.

view of "Alba Longa" seen from Monte Cavo during summer solstice

Digital model of the illumination of the Latium Volcano during summer solstice of the year 1000 BC, 4.45 am (the 3rd of July when applying the Gregorian calendar, 18 minutes from sunrise. View of the light belt from Monte Cavo, view direction east-west. Height exaggeration factor of the landscape 3.8x.

by
ANTONIA ARNOLDUS-HUYZENDVELD
(abstract)

(published in: "Archeologia w teorii i w praktyce", Warszawa (Poland), 2000)

see also Caroline Lawrence's blogspot on a day around Albano lake, the 17th of september 2008.
 

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, 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 Latium Volcano, south-east of Rome. The computer software Bryce 3D 4.0 was used for the modelling.
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.
Moreover it is remarked, that the particular morphological features of the Latium Volcano allow potentially the sun’s yearly evolution and crucial dates to be well observable either from the western rim of the Albano crater or from Monte Cavo.
In the model the solar data of 1000 BC were used, an approximation for the foundation date of Alba Longa. However, the rather 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" so well visible today as it must have been 3000 or more years ago.

winter real view of "Alba Longa" from Rocca di Papa, december 2008

photograph of the equinox, september 2001

aerial view of "Alba Longa" during winter solstice

Digital model of the illumination of the Latium Volcano during the winter solstice of the year 1000 BC, 8.05 am (the 30th of December when applying the Gregorian calendar), 21 minutes from sunrise. Within the circle the centre of the light belt, cast upon Castel Gandolfo. Height exaggeration factor of the landscape 3.8x. Sun’s position indicated by symbol.

aerial view of "Alba Longa" during equinox

the natural sundial during equinox

Digital model of the illumination of the Latium Volcano during the autumn equinox of the year 1000 BC, 6.33 am (the 2nd of October when applying the Gregorian calendar), 33 minutes from sunrise. Within the circle the last shadow of Monte Cavo retracting over the crater rim. Height exaggeration factor of the landscape 3.8x. Sun’s position indicated by symbol.

  
Some views of the lake of Nemi during the day
(photographs Caroline Lawrence)

The lake seen from the town of Nemi, with in the background a strip of the Tyrrhenian sea.

The remains of the Diana sanctuary are (just) visible in the lower right part of the photograph taken from Nemi town.

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 full moon rises close to Mount Albano when seen from Castel Gandolfo.

In the summer the sun rises more to the north and in the winter more to the south (see scheme below).

Sunrise over Mount Albano and the lake during the equinox-period, as seen from Castel Gandolfo, the 18th of september 2008, about 7h.20 legal time ....
 

... and a few minutes later (photographs Caroline Lawrence)

Full-moon rise over the Mount Albano and the lake during the equinox-period, as seen from Castel Gandolfo, the 16th of september 2008 (photograph Caroline Lawrence); the illuminated village is Rocca di Papa; actually full moon was on the 15th of september 2008, so here we are one day on the way to last quarter.

Digital model of the sunrise during summer solstice as seen from a position to the west of Castel Gandolfo; Mount Albano is the relief to the right.

Winter solstice sunrise seen from Castel Gandolfo: the Albano lake, between Monte Cavo (Mount Albano) and the Capuccini, the 21th of december 2008, 7h.53, direction towards east.
For more photographs see Facebook album My Alba Longa
 

A moment before winter sunrise seen from the plain to the WNW of Castel Gandolfo at a distance of 7 km, the 14th of januari 2008, 7h.47...