Mid-Winter Solstice Celebration Holiday 2015
A fabulous week holiday in Luxor visiting many ancient sites culminating in celebrating the mid-winter solstice at the magnificent temple of Queen Hatshepsut.
14th - 21st December 2015:
OrientationAstronomical Alignment in the Temples
by David Furlong
(This article runs over six pages. To download the whole article in pdf format please click here)
This part looks at the mortuary temple of Ramses III at Medinet Habu and the temple of Mut at Karnak.
Ramses III Temple at Medinet Habu (Plan 6)
Ramses ruled from 1190 bc to 1160 bc so these are likely to be the key dates for the temple’s orientation. However other temples existed on the site so we cannot discount the possibility that the temple’s orientation had already been determined at an earlier time.
Running the astronomy programme first to the 138º azimuth, towards the eastern horizon, showed no possible major star rising alignments or constellations for a period extending from 1160 bc to 2000 bc and beyond; looking in the opposite direction on a 318° azimuth, towards the Theban hills, initially appeared more hopeful.
The two potential alignments emerged for the stars Vega and Arcturus, which are both within the top seven brightest stars in the sky. However looking west towards the hills affects the visual extinction of the stars, which through calculation would have to be at a height of just over 9 degrees from a level horizon. Watching stars drop behind a hill, as opposed to disappearing on a level horizon has some advantages. It avoids a problem known as atmospheric extinction, where the density of the atmosphere affects the luminosity of any celestial body. The closer to the horizon the denser the atmosphere becomes, which is why it is possible to watch the rising or setting Sun. In a country like Egypt bright stars will disappear from a level horizon around a height of 2 degrees and fainter stars a degree or two higher. Star alignments have to take this extinction effect into account.
The figures for two different astronomical programmes are shown below for a height of 9 degrees:
Temple azimuth = 318 º
From these figures it is clear that the only possible 1st magnitude star that fits is Arcturus but only if we travel back in time, more than fourteen hundred years to the Old Kingdom period and this seems very improbable. So does this mean that there are no other possible stellar choices?
If we turn instead to look at the constellations there is one possible option; Cassiopeia, known for its giant ‘W’ formation in the sky, sets on the required bearing. Around 1190 bc the last tail star of the formation known as Segin, disappears on an azimuth of 318 º.
If stars played a part in the orientation of Ramses temple it must be to the faint star Segin and the constellation of Cassiopeia that we have to look and like the Karnak temple the azimuth was not aligned to face the star but away from it. Clearly in these cases it is the Nile that determines primary direction of the temples orientation.
Mut Temple at Karnak (Plan 9)
The calculated alignment azimuth is 19º- 14’ as opposed to the SB calculation of 18 degrees. The proximity to north suggests an orientation towards the tail stars of Ursa Major or the Great Bear, which we know as the ‘Big Dipper’ or ‘Plough’ but to the Ancient Egyptian was known as Meskhetu. This star grouping was perceived as the thigh and leg of a bull. To ancient minds the stars that never set were generally regarded with special awe; to the Ancient Egyptians they were the imperishable ones. We know from textual references (see Denderah temple) that these stars were used in the setting out of temples, but quite how is still unclear. Obviously it is not possible to sight to their rising or setting positions, so how might this constellation have been used. When observing the tail stars of Ursa Major, it becomes apparent that at certain times they are in vertical alignment to the ground. Indeed four of the seven stars, Merek, Megrez, Alioth and Mizar, very nearly line up in this way. Being high in the sky about twenty degrees above the horizon and in an arc of only twenty degrees they are not difficult to observe. By using a simple weighted plumb bob, which the Egyptian called the Merkhet, it would have been easy task to establish an orientation, when these stars were in vertical alignment. If we take a date of around 1190 bc for the main temple construction we find such an alignment to Meskhetu on an azimuth of just under 19°, which neatly fits the temple and sphinx avenue orientation. The difficulty here is that this alignment only works close to a date of around 1200 bc. Three hundred years earlier, during the reign of Hatshepsut, the Meskhetu alignment would have been two degrees off the bearing.
The Mut temple, along with its attendant sphinx avenue could have been astronomically aligned to the suggested stars of constellation of Ursa Major or Meskhetu for the dates given. The other possibility is that the intended alignment was to the centre of the Great Hypostyle Hall and as such had nothing to do with the stars.
The temples studied here only scratch the surface in relation to the many extant temples in Egypt. Further work is required in this area, which fortunately now can be extensively done with the aid of computers.
All material copyright David Furlong 2010