Glossary X
At a lunar backsight where permanent or temporary ancillary extrapolation gear has been set up there should be a length preserved between major stones which is the 4G for this site. This 4G represents, on the ground, the lateral distance an observer must move in order to 'shift' the Moon through the declination range K. K is the change in the Moon´s position during the 24 hours preceding a standstill. At a Major Standstill it is 46.5 arc minutes and at a Minor Standstill 30 arc minutes. See also- K, ANGULAR DISPLACEMENT, EXTRAPOLATION PROCEDURE, LUNAR STANDSTILL.

Carleton Bank, Cleveland Hills, North Yorkshire.

Wsolsticeset_2005_net

Winter solstice sunset on Carleton Bank, North Yorkshire.


Colin Swinton.

Colin Swinton is a teacher of water-colour landscape art and a photographer. He has done much photographic field research in the Cleveland Hills investigating the astronomical positioning of tumuli and cairns. He is based near Thornborough and has examined the Thornborough henge alignments for their astronomical potentials. Also he has collected good quality photographs of sunsets on a hill slope named Carleton Bank and discovered it has Obliquity observation potentials from two directions both north and south.

The Angle of Obliquity to the Ecliptic on Carleton Bank.

At the winter solstice 2005 Swinton secured a chain of high quality images of the sun rolling down Carleton Bank from a camera position behind a small stone set in the apron bank of a Bronze Age tumulus. From this backsight the upper limb of the setting Sun at the winter solstice of 1600 BCE would flash down the entire length of the north- western slope of Carleton Bank. This prolonged phenomenon is only possible on hill slopes which have the same angle of descent as the Angle of Obliquity to the Ecliptic.

Wsolsticeset 2005 detail

When a clear photograph of the sun near a horizon feature is digitised then the exact declination of the sun at that moment may be read from the astronomical tables in the USNO online data services and an extrapolation made for the precise declination of the horizon feature. Further extrapolations may then be made to any epoch in the past using the formula 0.72 arc minutes per century

Digital extrapolation

The solstitial sun no longer reaches the maximal positions on the horizon as in the Bronze Age however with images of this quality fine digital extrapolations of the position of the sun in past ages may be established.
Using the diameter of the sun, (31.6 arc minutes), as the scale of these images, and the estimated Rate of Change of Obliquity, (0.72' per century), we may make good estimations in which years the Green Flash might have been seen on the flank of Carleton Bank from any stance.

Mirror alignments.

Mirror alignments
On an ideal flat landscape the solstitial alignments would lay as a cross and a prominent alignment might have multiple functions both before and after the foresight, summer and winter.
When a prominent foresight such as Carleton Bank is identified the researcher should try to establish if the alignment might continue after the foresight and support another alignment looking backward to the first foresight and, hence, the opposite solstice. The winter solstice sunset line to Carleton Bank might support a summer solstice rise...and a winter solstice rise is the corollary of a summer solstice set..etc.

Accordingly Colin Swinton followed his original alignment over Carleton Bank and map searched this line looking for a possible backsight observing in reverse to Carleton Bank winter solstice sunset.
At around 20 miles,(32 kilometers), he struck the central feature of the group of important prehistoric monuments of the Thornborough Henges, popularly known as the Stonehenge of the North.

Thornborough Henges.

On the fertile ground near the confluence of the Swale and Ure rivers in Yorkshire, Northern England lie a remarkable group of prehistoric monuments. More than six stadium sized earthen henges, a large tumulus and one of the largest stone rows in Britain appear to have been erected in straight alignments across several kilometres of this valley. Several investigators over the years have remarked on the rigorous positioning of these monuments.

The large entrance tumulus

Carleton Bank from Henge.
Carleton Bank at 20 mls,(33kms). Azimuth 47°
At the southern entrance to the central henge in the Thornborough row Swinton has taken a clear image of Carleton Bank over the large tumulus marking this entrance. The Cleveland Hills with Carleton Bank are prominent to the unaided eye at 20 miles,(33km) distance, in clear weather. From the tumulus the Bank has a compass bearing of @ -8°47' - very near the position of the rising sun at a summer solstice for this latitude. This is as we should expect when following the mirrored alignment from the winter solstice sunset on the far side. For full verification of the intent of this alignment a train of photographs of the rising sun would be required taken near the day of the summer solstice.

Photo observation of sunrise 30th June 2006

Carleton Bank summer solstice 2006.
Carleton Bank 30 June 2006.
On the 30th June 2006 Colin Swinton took a series of images of the rising sun from a camera stance behind the large tumulus in line with the northern slope of Carleton Bank in the Cleveland Hills. This chain of images is of sufficient quality to render an accurate position of the sunrise track with reference to the slope of Carleton Bank. The precise declination of the sun at this moment was read from the online Astronomical Data Services of the USNO,(NASA).


Carleton Bank summer solstice 2006 detail.
Carleton Bank 30 June 2006 detail.

Thornborough Henge Tumulus to Carleton Bank.

When the photographic distance in arc angle between Carleton Bank and the position of the rising sun in this composite image is divided by 0.72 arc minutes we arrive at a date of 2655 BCE for the positioning of the great tumulus and, perhaps, the establishment of the southern entrance of the central henge.
Archaeological opinion for the date of the commencement of the building period of the Devil's Arrows stone row and Thornborough Henges is 2700 BCE.