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Who is
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Sun and Moon Lozenge Applet

   
Using the scroll bar arrows to set the latitude.

Select from the menu to show or hide details:

applet details

Bush Barrow - near Stonehenge, 51.17 N - is a site of the early British Bronze Age (ca. 2000 BC), excavated in 1808 by Sir Richard Colt Hoare and William Cunnington. The barrow contained a male skeleton with rich funerary goods, including a large 'lozenge'-shaped sheet of gold, about 0.5 mm thick.

lozenge
Source: Wikipedia

The parallelogram (lozenge) is measuring 18 cm across. It might have served as a solar and lunar calendar, using the sight lines pointing in the direction of Sun solstices and lunar standstills.

losenge applet sun
                        moon

Azimuth angles of the Sun (red):
    rise and set at summer solstice
   
rise and set at winter solstice
   
rise and set on May 1 (Beltane), declination about +15
    rise and set on November 1 (Samain), declination about -15 

Azimuth angles of the Moon (blue):
    northern and southern rise and set at major lunar standstill
   
northern and southern rise and set at minor lunar standstill

The azimuth angle az of rise and set depends on the declination δ and the latitude φ. Neglecting atmospheric refraction the angle for a mathematical horizon can be computed by the formula:
cos az = sin δ/ cos φ

At 51.17 N the sizes of the arcs for rise and set are (2000 BC):
    solstices: 80.6
    solar arc May 1 to November 1: 49.1
    major lunar standstills: 101.6
    minor lunar standstills: 61.8

At 51.17 N the ratio of the lozenge axes NS/EW is 0.821.


Lunar standstills
                      

Web Links

Bush Barrow (Wikipedia)

Clandon Barrow (Wikipedia)

Bush Barrow Gold Objects (Wiltshire Heritage Museum)

D.P. Gregg: The Stonehenge Code (PDF)

Clive Ruggles: Ancient Astronomy - An Encyclopedia of Cosmologies and Myth (PDF), p. 52

Lunar standstill (Wikipedia)

Books, Articles
Archibald Thom: The Bush barrow gold lozenge: is it a solar and lunar calendar for Stonehenge?
in: Studien zur Megalithik - The Megalithic Phenomenon, edited by Karl. W. Beinhauer, Beier & Beran, Weissbach 1999. p. 289 - 307.

Last modified: 2015, Oct 19