Observing from the Stonehenge...

(A) The Rising and Setting Position of the Sun & Moon

Astronomer, Alexander Thom, had an observational theory.

Relating back to the four Station Stones (SS), 91, 92, 93 and 94, Thom and other astronomers noted that it formed a perfect rectangle, which is remarkable considering that the long axis of the rectangle is around 300 ft in length. The Sarsen ring formed a circle 97 ˝ ft across in which every upright was, on average, amazingly less than 3 inches out of position!

Thom investigated this geometric precision closely in around three hundred megalithic monuments all over Britain.

During his study of these monuments he came across two standard units of measurement, which he called the 'Megalithic Fathom' (equivalent to 1.6 m or 5.44 ft) and the 'Megalithic Yard' (equivalent to 0.83 m or 2.72 ft - 8 ˝ inches short of a standard English yard, as mentioned earlier). Thom found that the Megalithic Yard had been used at Stonehenge, in the spacing and positioning on the Sarsen circle uprights. Figure 2, below, illustrates the many alignments among the stones of Stonehenge I and Stonehenge III.

FIGURE 2: Stonehenge I and III Astronomical Alignments

Stonehenge I and III alignments (40 KB) - links to a larger 64 KB version

Figure 2 shows that an observer looking from SS92 (Station Stone 92) over SS91 would see the summer solstice sunrise, as he would if standing behind the Altar Stone (stone 80) and looking over stones C and B in the Avenue, just to the left of the remaining Heel Stone. Many of the alignments are at exact right angles. This is due to latitude at which Stonehenge was built. The exact rectangle of alignments through the Station Stones can only be achieved on (or very close to) 51° North, that is, at Salisbury’s specific latitude. Once again, this demonstrates the astronomical knowledge the Neolithic populations possessed.

TABLE 2: Stonehenge I Astronomical Alignments

Astronomical Event

Alignment Stones

From...

...to...

Summer solstice sunrise

SS 93

SS 94

SS 92

SS 91

Summer solstice sunset

Stone G

SS 94

Winter solstice sunrise

SS 94

Stone G

Winter solstice sunset

SS 91

SS 92

SS 94

SS 93

Summer solstice moonrise, major standstill

SS 93

SS 92

Summer solstice moonrise, minor standstill

SS 93

SS 91

Winter solstice moonset, major standstill

SS 91

SS 94

Winter solstice moonset, minor standstill

SS 91

SS 93

Most southerly moonrise

SS 94

SS 91

Most northerly moonset

SS 92

SS 93

Equinox sunrise

SS 94

Stone C

Equinox moonrise

SS 94

Stone B

[ SS = Station Stone ]

 

(B) Planetary Observations

M. W. Postins wrote a booklet entitled Stonehenge: Sun, Moon, Wandering Stars in 1982. Postins built two scale models, which he called the 'Temple model' (Stonehenge III) and the 'Enclosure model' (which shows outlying features such as the Aubrey Holes and Station Stones of Stonehenge I and II). In his booklet, Postins states that the five trilithons represented the planets visible with the naked eye.

Mercury and Venus are the two planets in the sky that keep in closest association with the Sun. The eastern and northern lowest trilithons have alignments through the Sarsen circle relating directly to the Sun (see Figure 1). Therefore, it was suggested that these two lowest trilithons represented Mercury and Venus.

The two intermediate trilithons represented Mars and Jupiter because they are associated with lunar alignments. Mars and Jupiter are associated with the Moon due to their paths through the Zodiac. Because of this they are not linked to sunrise and sunset events like Mercury and Venus, but may be observed close to the Moon as they all follow similar paths along the ecliptic. The two intermediate trilithons align with major and minor positions of the Moon, which the Altar Stone (stone 80) also does through gaps in the Sarsen circle (see Figure 1).

The Great trilithon represented Saturn because Saturn moves very slowly across the sky compared to the other four planets. This stately pace may have indicated to the people who built Stonehenge that Saturn held some sort of 'senior' position in the heavens.

FIGURE 1: Stonehenge III (Temple) Astronomical Alignments

Stonehenge III alignments (30 KB) - links to a larger 50 KB version

 

The Sun-aligned low trilithons cannot be differentiated in order to determine which planet (Mercury or Venus) each represents. Neither can the Moon-aligned intermediate trilithons representing Mars and Jupiter.