Last year saw a large number of people (including Druids) turn up at Stonehenge on the wrong day in 2009? I thought I would clarify the correct ‘Winter Solstice’ day for 2010 to save any embaresment. The summer solstice is always on the 21st, however the winter solstice can fall on the 21st or the 22nd. The celebration does not always fall on the same date as the solstice because the modern year does not correspond precisely to the solar one.
The exact time for the Winter Solstice is December 21st, 11.39pm (UK time). The sunset on the 21st is at 3.53pm and the sunrise on the 22nd of December at 8.04am. Exceptionally, you can also expect a full moon on December 21th.
English Heritage did not confirm the date for Open Access for Stonehenge for the Winter Solstice yet, but most likely this will be dawn on the 22nd of December. (The sunrise on the 22nd is closer to the actual solstice than that on the 21th of December.) Expect a short period of access, from approximately 7.30 to 9.00am
Stonehenge is carefully aligned on a sight-line that points to the winter solstice sunset (opposed to New Grange, which points to the winter solstice sunrise, and the Goseck circle, which is aligned to both the sunset and sunrise). It is thought that the Winter Solstice was actually more important to the people who constructed Stonehenge than the Summer Solstice. The Winter Solstice was a time when most cattle were slaughtered (so they would not have to be fed during the winter) and the majority of wine and beer was finally fermented.
Gerald Hawkins’ work
Gerald Hawkins’ work on Stonehenge was first published in Nature in 1963 following analyses he had carried out using the Harvard-Smithsonian IBM computer. Hawkins found not one or two alignments but dozens. He had studied 165 significant features at the monument and used the computer to check every alignment between them against every rising and setting point for the sun, moon, planets, and bright stars in the positions they would have been in 1500 BC. Thirteen solar and eleven lunar correlations were very precise against the early features at the site with precision falling during the megalithic stages. Hawkins also proposed a method for using the Aubrey holes to predict lunar eclipses by moving markers from hole to hole. In 1965 Hawkins wrote (with J. B. White) Stonehenge Decoded, which detailed his findings and proposed that the monument was a ‘Neolithic computer’.
Stonehenge – An Asronimical Calandar
Stonehenge features an opening in the henge earthwork facing northeast, and suggestions that particular significance was placed by its builders on the solstice and equinox points have followed. For example, the summer solstice sun rose close to the Heel Stone, and the sun’s first rays shone into the centre of the monument between the horseshoe arrangement. While it is possible that such an alignment can be coincidental, this astronomical orientation had been acknowledged since William Stukeley drew the site and first identified its axis along the midsummer sunrise in 1720.
Stukeley noticed that the Heel Stone was not precisely aligned on the sunrise. Year to year, the movement of the sun across the sky appears regular. However, due to temporal changes in obliquity of the ecliptic, illumination declinations change with time. The purported Heel Stone alignment with summer solstice sunrise would have been less accurate four to five thousand years ago. The Heel Stone, in fact, is located at 1/7th of circumference from due North, as noted by archaeologist James Q. Jacobs. Stukeley and the renowned astronomer Edmund Halley were to attempt what amounted to the first scientific attempt to date a prehistoric monument. Stukeley concluded the Stonehenge had been set up “by the use of a magnetic compass to lay out the works, the needle varying so much, at that time, from true north.” He attempted to calculate the change in magnetic variation between the observed and theoretical (ideal) Stonehenge sunrise, which he imagined would relate to the date of construction. Their calculations returned three dates, the earliest of which, 460 BC, was accepted by Stukeley. That was incorrect, but this early exercise in dating is a landmark in field archaeology . .
Early efforts to date Stonehenge exploited tiny changes in astronomical alignments and led to efforts such as H Broome’s 1864 theory that the monument was built in 977 BC, when the star Sirius would have risen over Stonehenge’s Avenue. Sir Norman Lockyer proposed a date of 1680 BC based entirely on an incorrect sunrise azimuth for the Avenue, aligning it on a nearby Ordnance Survey trig point, a modern feature. Petrie preferred a later date of AD 730. The necessary stones were leaning considerably during his survey, and it was not considered accurate.
An archaeoastronomy debate was triggered by the 1963 publication of Stonehenge Decoded, by British-born astronomer Gerald Hawkins. Hawkins claimed to observe numerous alignments, both lunar and solar. He argued that Stonehenge could have been used to predict eclipses. Hawkins’ book received wide publicity, in part because he used a computer in his calculations, then a rarity. Archaeologists were suspicious in the face of further contributions to the debate coming from British astronomer C. A. ‘Peter’ Newham and Sir Fred Hoyle, the famous Cambridge cosmologist, as well as by Alexander Thom, a retired professor of engineering, who had been studying stone circles for more than 20 years. Their theories have faced criticism in recent decades from Richard J. C. Atkinson and others who have suggested impracticalities in the ‘Stone Age calculator’ interpretive approach.
See you all at the Winter Sostice
Merlin @ Stonehenge
The Stonehenge Stone Circle Web site