Megalithic Month alignment 
at Maeshowe


Victor Reijs

The Netherlands

1 Introduction

Maeshowe is one of the biggest and best preserved chambered cairns in Orkney, up north of Scotland. It was build around 3000 BCE and is at least aligned with the sunset of winter solstice day. But another orientation is presented in this paper. This paper will reveal the path of discovering a Megalithic Month alignment of Maeshowe; after first providing the history on this discovery, the ideas how to model a megalithic buildings are presented. The conclusions of comparing this (computer) model with reality are given in the evaluation section. And at the end of the paper, the future steps will be revealed, because there are of course still more things to be discovered!


The history of my discovering a new orientation at Maeshowe started with an Internet friendship with Doug Schwartz in 1995. He stated that Maes Howe was probably not a winter solstice building, but a Yule building, which meant that it was aligned to a period before and after winter solstice and thus not the solstice itself. With his help and a recommendation letter from Euan MacKie, I got permission from Historic Scotland to make measurements in August 1996 within Maeshowe. These measurements were accurate enough to base a computer model on. From this model it became instantly clear that the passage and chamber were certainly not aligned to winter solstice day only, but for at least a period of some 30 days before and after winter solstice day the sun would penetrate towards the back wall of the chamber. This long period of sun on the back wall of Maeshowe was communicated to the custodians of Maeshowe, and they started observations in Nov., Dec. 1996 and Jan. 1997. These observations brought to light that indeed light was seen as early as mid Nov. on the back wall!

Sunset on 15:03 GMT, Nov. 23rd, 1996 (©, S. Hodnett, 1996)

Because this unique information was never before so clear, more study has been done. In May 1997 a new visit was made. During this visit it became clear that there was a possibility of a reappearance of the sun behind Ward Hill (analogous to the reappearance of the moon at Callanish I in Lewis, Scotland [Ponting]). This reappearance  was not recognized earlier, because during my Aug. 1996 visit too much haze obscured Ward Hill from view!
Incorporating this information in the computer model, the reappearing sunlight will be seen on the back wall some 22/23 days before and after winter solstice day 2800 BCE. This 22/23 day period is called a Megalithic Month (MM, or 1/16th of a year) by [Thom].

To film this phenomenon the custodians of Maeshowe were asked to note more precisely the sunsets and possible reappearance's in Nov. and Dec. 1997. As expected, on Dec.2, 1997, the sun was seen reappearing from behind Ward Hill and shining on the back wall, thus proving the computer model. In Dec. 1997 and Jan. 1998 a video camera continuously recorded the sunsets within the Maeshowe chamber [Reijs-c], this provided more accurate information for the computer model. Unfortunately, no reappearing sunlight on the back wall has been video taped due to bad weather in Jan. 1998.


Before starting to make the model, one has to study and measure in the field. This section will provide some insight into the tools used and how the basic measurement were transformed into a model of Maeshowe.

3.1 Tools

The tools used to make the model for predicting the alignments at Maes Howe, can be subdivided in the following items:

3.2 Model

 The following items are determined to make a valid model of a building:
  1. A plan and section of the building

  2. Beside defining a reference grid in the monument (line M), a global idea of the building can be seen in the plan and section made by Calder, 1946:

     Plan of Maeshowe

      Section of Maeshowe

  3. The minimum and maximum azimuth at which the sun will shine on the back wall of the chamber.

  4. These minimum and maximum azimuth (respectively: line A and line B) are determined by four stone slabs in the passage. The measured positions of these horizontal limiting stone slabs are used within the computer model.
    The actual azimuth of these lines is determined by using several tools:
    Line A
    Line B
    OS map/pictures
    Sun's rim
    There is yet no other literature that provides information on these two lines. Most of the time one finds in literature only an average of these two lines, which does not say much for celestial alignments!

    In [MacKie] azimuth measurements by theodolite have been done of the right and left hand slope of Ward Hill. Comparing this with my measurements:

    Slope of
    Ward Hill
    Sun's rim
    Left 216° 59' 217° 19' +/- 10'
    Right 222° 53' 222° 29' +/- 10'
    These values are well within the same neighborhood, so the azimuths determined by the sun's rim are accurate, and are used in the model.
  5. The position of the vertical limiting stones

  6. Several cases from the literature are evaluated:
    1. Petrie, 1861

    2. A high entrance, at the height of the passage blocking stone a horizontal stone.
    3. Gibb, 1862

    4. A low entrance, fully blocked by the passage blocking stone
    5. Calder, 1946

    6. The present situation, with a high entrance.
    7. Burl, 1981

    8. A high entrance at the height of the passage blocking stone, a horizontal slab (similar to the roof box at Newgrange). Partially comparable with Petrie.
    9. Reijs, 1997

    10. A low entrance almost blocked by the passage blocking stone, where a gap of some 2-6 [cm] still exists. Partially comparable with Gibb.
  7. The altitude of the horizon

  8. The altitude has been determined by photographic measurements. A picture has been made of the horizon. This picture has been digitized, and the altitude calculated. In the below pictures, these altitudes are provided (y-scale from -1° to +2°):
  9. The altitude and azimuth of the sun

  10. This information was obtained from a planetarium computer program (SkyMap, which incorporates parallax, precession, nutation and astronomical refraction). It has been determined for the periods around the dates: Dec. 21st, 1996 CE and Jan.13th, 2799 BCE.


Let's first investigate the observations obtained in the present. The sun shines on the back wall from at least 30 days before winter solstice to 30 days after winter solstice. A very long time!

At present days: On around 19/20 days before and after winter solstice the sun will reappear from behind Ward Hill. (this reappearance is not a feature of Maeshowe itself, but rather of the local landscape). The reappearance can be viewed on the back wall. Because of this dynamic process of reappearance, a video would be needed to show how it is seen on the back wall of the chamber. Because no video recordings are yet available for sunny days, an animated picture has been made with the computer model [Reijs-a].

The computer model of Maeshowe is accurate within +/- 1 [minutes of time] and +/- 2 [cm] for determining the timing and location of the sunlight on the back wall of the Maeshowe chamber.

Using the computer model for 2800 BCE, the following information on when the sun will shine on the back wall (depending on the vertical limiting stones, see section: Model) is determined:

The reappearance of the sun behind Ward Hill occurred in 2800 BCE around 22/23 days before/after winter solstice. This 22/23 day period is termed by many (e.g. [Thom] and [Thomas]) a Megalithic Month (or 1/16th of a year).

The bright and shaded part defines the moments the sunlight will be on the back wall when using the Petrie or Burl limiting stones. Thus the sunlight will be on the back wall at winter solstice day only for a few minutes. Further away from winter solstice day the amount of time increased to 25 minutes at some 21 days before/after winter solstice. From 22 to 24 days before/after winter solstice (1 MM) the reappearance of the sun takes place: the sunlight is some 25 minutes on the back wall, then it disappears behind Ward Hill (and thus no light is in the chamber) and then that a short flash of light on the back wall. After these days, the sunlight will be on the back wall again in one go and will vanish fully from the back wall after more then 30 days.

The shaded area is depicting the moments that the sunlight will be on the back wall using the Gibb or Reijs limiting stones. The difference between Gibb and Reijs is that in Gibb there will only be sunlight on the back wall, when the passage blocking stone is in its recess (remember in this case there will always be much sun on the floor of the chamber and in passage on other days). With the Reijs's limiting stones there will only be light on the back wall during this shaded period and never in/on the passage/chamber. In both cases the reappearing sunlight around 22/23 days (1 MM) before/after winter solstice is seen on the back wall.


The major conclusions to be deducted from the above results are:
  1. Some uncertainties with regard to the possible rebuilding of the first part of passage still exist.

  2. After the excavation in 1861 [Petrie], the first part of the passage was rebuilt. This idea also stems from the difference in the plans of Maeshowe made by Petrie and Gibb. Petrie provides a plan as if there is a kind of roof box above the entrance, while Gibb draws this as a lower ceiling. The truth will never be known (even things from less then 150 years ago are vague).
    The bend in the passage is almost unquestionable original. The nice thing about this bend is that the bend itself had no effect on the alignment of winter solstice day at all, but it makes the alignment for 22/23 days before/after winter solstice much more accurate.
  3. The computer model more of Maeshowe predicts the light patch on the back wall accurately.

  4. The model is able to predict the timing and location of the light patch on the back wall within +/- 1 min and +/- 2 cm respectively. This gives confidence in using the model to make predictions in both the past and present.
    Remember the model of the building does not determine the reappearance of the sun; that is determined by the path of the sun and the local landscape (the azimuth of Ward Hill's slope and the altitude of the low hill some 2.5 km south of Maeshowe).
    A 3D model of Maeshowe and a 3D terrain of the land strip between the two lakes: Loch of Stenness and Loch of Harray related to Hoy [Reijs-b] has been made, so that one is able to fly thought this virtual world.
  5. An aperture between passage blocking stone and passage ceiling, makes a dramatic sunset around one Megalithic Month before/after winter solstice.

  6. From simple measurements there is a small gap [some 5 cm] between the passage blocking stone and the lower ceiling (lowered according to Gibb). If this gap was indeed on purpose (see Future steps section), the light effects within the chamber is much more dramatic when the passage blocking stone closed the entrance. A small patch of bright light would have penetrated only around 22 to 30 days before/after winter solstice.
  7. Dual alignments at passage mounds are more common.

  8. Beside Maeshowe, other buildings have also more then one alignment. For instance, measurements at Newgrange and Knowth (both in Ireland), show that, beside light through the passage, also light during midday of the longest day can penetrate through a hole below the capstone of the corbelled roofs!
  9. Looking at the simulation of the light patch on the back wall around 2800 BCE, Maeshowe could very well be a 'Megalithic Month' building beside a 'Winter Solstice' building.


Future steps

Lots of things have been learned during the two years of investigations, but more needs to be done.
The following items will be taken up during my next visit to Orkney in the winter of 1998:
  1. Videotape the reappearance's of the sun behind Ward Hill (seen from both the outside and inside of Maeshowe).
  2. Make a mock-up of the passage blocking stone and see what the effect will be on the light path in passage and chamber.
  3. Study the layout of the steep slopes of Ward Hill (Glen of Greor) and the Cuilags (Kame of Hoy) and the megalithic buildings in Stenness environment. These buildings have been build around the two reappearance's of the sun at both winter solstice and a Megalithic Month before/after winter solstice. The general idea of this reappearance of the sun is also described in [MacKie].

  4. The below pictures depicts this idea:

    The relationship between steep sloops near Ward Hill and Cuilags and
    the buildings near the land strip between Loch of Harray and Loch of Stenness.
Ward Hill plays a special role! Even in the 18th and 19th century it radiated magnificent light around the longest day. The following quotation from The Pirate (Sir Walter Scott, 1821) in [Bremner] states:
"At the west of this stone [the Dwarfie Stone] stands an exceeding high mountain of a steep ascent, called the Ward Hill of Hoy, near the top of which in the month of May, June and July, about midday [changed by VR: in original text midnight], is seen something which shines and sparkles admirably, and which is often seen a long way off. It has shined more brightly before than it does now, and though many have climbed the hill, and attempted to search for it, yet they could find nothing. The vulgar talk of it as being some sort of enchanted carbuncle, but I take it rather to be some water, sliding down the face of some smooth rock, which, when the sun at times shines, on, the reflection, causeth that admirable splendour."

7 Acknowledgments

The list of people that have helped me is long. I would especially like to thank Doug Schwartz and Euan MacKie, who wrote recommendation letters so that Historic Scotland provided me the access to Maeshowe. Many people, especially Patrick Ashmore, Sue Hodnett and Moira Moncrieff of Historic Scotland, have willingly provided support in helping me to make measurements! Thanks to the Maeshowe project (a cooperation project between the author, Charles Tait and Historic Scotland) it was possible to videotape the sunsets in Dec. 1997 and Jan. 1998. Furthermore I want to thank Neil Mortimer and Douglas Schwartz for their help in reviewing this paper.
Of course, many thanks to all the unmentioned people who are also in my mind!

Last, but certainly not least, I want to thank my partner, Joke Jansman, for her continuous support of my work. She spent many hours alone, because I have an urge to try to decipher a mystical building.

8 References

Maeshowe, Ashmore, P., HMSO, Historic Scotland, ISBN 1 900168 06 5, 1995, Edinburgh
Hoy - The dark enchanted isle, Bremner, J., Bellavista Publications, 1997, ISBN 0 9525350 2 5.
By the light of the cinerary moon: chambered tombs and the astronomy of death, Burl, A., in Ruggles and Whittle (1981), pp 243 - 274.
Maeshowe, Childe, V.G., Proceedings of the Society of Antiquaries of Scotland, 88, 1956, page 155-171
Knowth and the passage tombs of Ireland, Eogan, G., London, Thames & Hudson, 1986, ISBN 0-500-39023-1
Antiquities of Stenness parish, Frazer, J. Proceedings of the Orkney Antiquarian Society, 4, 1925, page 18-22
The chambered cairns of Orkney, Davidson, J.L., Henshall, A.S., Edinburgh University Press, ISBN 0 85224 547 5, 1989.
Maeshowe and the winter solstice ceremonial aspects of the Orkney Grooved Ware culture, MacKie, E.W., Antiquity 71, June, 1997: 338-59.
Newgrange, O'Kelly, M.J., London, 1982, ISBN 0-500-27371-5
Notice of the opening of a tumulus in the parish of Stenness on the mainland of Orkney, Petrie, G., Archaeological Journal, 18, page 353-358, 1861
Decoding the Callanish complex. Some initial results, Ponting, M. and G., Article out of B.A.R. 88, 1981; Astronomy and society in Britain during the period 4000 - 1500 B.C., editor Ruggles, C.L.N. and Whittle, A.W.R., ISBN 0 86054 130 4, page 63-110
Maeshowe, Reijs, V.M.M., 1997, http://
Maeshowe and its environment in 3D, Reijs, V.M.M., 1998,
Megalithic cam-page at Maeshowe, Reijs, V.M.M., 1997,
Maeshowe's Megalithic Month alignment, Reijs, V.M.M., 1998, 3rd Stone, Oct.-Dec. 1998, page 18-20.
Notice of excavations in the chambered mound of Maeshowe in Orkney, Stuart, J., Proceedings of the society of Antiquity of Scotland, 5, page 248-278, 1965
Megalithic sites in Britain, Thom, A., Clarendon Press, Oxford, 1967
Irish symbols of 3500 BC, Thomas, N.L., Mercier Press, 1988, ISBN 0 85342 856 5.

Last major content related changes: May 31, 1998