There are two planes, which we have discussed before that are crucial in discovering where objects are in the sky. One is the celestial equator. This is the extension of the equator out into space. You can find this by coming 90 degrees down from the point in the sky on which things appear to pivot.

The other is the ecliptic which is the line which the sun follows throughout the year. The ecliptic is tilted at 23 degree angle to the celestial equator.

Astronomical horizon is a line tangent to the earth at the point where the observer is standing. May differ substantially from visible horizon where many factors may inhibit view:

Trees, building, mountains and other geological phenomenon as well as atmospheric phenomenon.


Non-Viewer Centered

Right ascension and declination are most commonly used by astronomers.

Declination is given in degrees an object is away from the celestial equator - if north the number is + and if south the number is -

Right ascension is the distance a star is from the first point of Aries aka the vernal equinox.

Viewer Centered

Viewer centered uses 2 coordinates: azimuth and altitude

For azimuth, start at due north, and count around circle in degrees. Full circle is 3600. How high above horizon is the altitude.

Finding stars is often with mnemonic devices:

Certain constellations and asterism are pivotal (usually obvious):

Big Dipper => Polaris, Leo
Orion => Sirius; Gemini; Taurus
Summer Triangle: is made up of Vega (Lyra the Lyre), Deneb (Cygnus the swan), Altair (Aquilla the eagle).

ARC to ARCTURUS, SPEED to SPICA, meet corvus the crow on the back of Hydra the water snake

Follow the three stars in Orion’s belt to Sirius

Pointers in the dipper point to Polaris - the pole star
Continue to Cassiopeia (looks like a “W” or “M”)

Follow the pointers in the opposite direction, land on the back of LEO the Lion


Orion was killed by scorpion so Orion and Scorpio are always 180 degrees apart,



Needs to be fast enough to see, but slow enough to be considered. Daily path through sky may be first thing noticed, although it is so common perhaps went unmentioned.

Moon is first object noticed going through phases. Also has N-S rising and setting which is monthly, although there are extremes.

Sun’s position is always changing as well. Perhaps second thing of importance. North south movement also apparent.


Only movement seems to be nightly and annually, but their consistency may have proven more interesting. Always rise and set in the same place relative to the horizon, unlike the sun, moon and planets which all wander through the sky against the “fixed” stars.

The very IDEA that they wander against the fixed stars seems to imply that the idea of the “fixed” stars is already clear.


A number of large drawings on the ground exist. Among these are The Uffington White Horse, The Wilmington Long Man, and the Cerne Giant

The Uffington White Horse (3230 BC?)

Marked the rising of Taurus

Interesting problem is stress on form of animal, which is not really very horse like. In fact from several positions of importance, the forms is virtually missing.

Assumption: Overall size and form and “lay” have not changed. Horse is on Mountain, curving road (Gallery) below.

When viewed looking East, three stars Aldeberan, Gamma Tauri and zeta Tauri rise conspicuously over the hills, with gamma marking the eye of the horse, and Aldeberan the penis.

Horse lies on ridge on West side. Looking down from the ridge, the horse loses it shape, but is a perfect marker for the setting of Rigel.

The Wilmington Long Man (Orion)

Lots of speculation about it. Nebuchadnezzar; Colossus of Rhodes; Zeus; polite copy of Cerne Giant but it is older than all of them.

Outline of a man looking roughly northwards toward village of Wilmington. Sort of looks like a skier. Some have depicted him with scythe and rake rather than 2 spears and argued for a demilitarized Wodin as a result of Christianity. EYES ARE MARKED BY HOLLOWS AND NOSE AND MOUTH BY RAISED MOUNDS. Area seems to have been worked and made slightly concave. Poles are 70.3 and 71.8 meters, with distance of 35.6 and 34.8 meters between them.

Figure is rather elongated, but from spot near the road, becomes foreshortened. Ditches on side may have carried off rain water.

Orion would have appeared to set here about 3480 BC with Rigel touching the left staff and then “walking” down the hill directly over the drawing.

Cerne Giant (Hercules?)

Many thought it to be Orion, but unlikely from astronomical approach. Closer to Hercules in terms of the club and bent arm which usually bears a lion skin. Stars of Hercules rise close to this, but time is near 20 BC to 200 AD reasonably Roman influence. Uncertain about stars and so on.



Thom felt that in the construction of stone rings and other monuments a different scale was used, namely the Megalithic yard which he believed was 82.9 cm or 2.72 feet

STONEHENGE HAS BEEN APPROACHED BY A NUMBER OF RESEARCHERS. Most popular has been HAWKINS, but a recent book by NORTH argues with some of his material

BARROWS - raised mounds of earth and EARLY MEGALITHS (STANDING STONES)

Barrow: a mound deliberately erected out of earth and other material (chalk, stone wood) and having a conscious architectural structure. Often for burials, but not always.

Long barrows: like loaf of bread. Often chambered are typical of Neolithic; Round barrows are typical of bronze age (First point where copper and its alloys were first used. Dates depend on place. For Britain Early Bronze is seen as 2500 BC - 1800 BC; Middle 1800 BC - 1300 BC; Late 1300 BC - 700 BC

Barrows had burials. Directions seem to vary from place to place of both barrows and bodies in them.

Barrows may have made “artificial” horizon for sightings

REMEMBER actual vs. astronomical horizon.


Problems of “accidental sightings” that is to say that the alignments are likely to happen given the number of stars, solar and lunar positions and “markers” in natural phenomenon.

Problem: Where is the viewer standing?
When is all this going on?

Stone structures occur in many places - and at many times. For example, NAMORATUNGA II in northwest Kenya. Date for the related Namoratunga I (130 miles south) which has a burial at about 300 BC.

At both Namoratunga I and II a GRAVE was encircled by rocks. At N II there are 19 more megaliths arranged in an odd pattern with no burials surrounded by uprights. These seem to align with Bellatrix (Orion); Aldeberan (Taurus); the Pleiades, Saiph (Orion); Sirius (Canis major); and Triangulum and Orion’s belt. It is interesting to note these are the same stars used by the ancient Egyptians.

The distances are too close for a real “alignment” (i.e. from the point where the observer stood to the stone is so close, a serious alignment is not possible; but a general indication of a rising is possible. These stars might have been important in calendars etc.

The Konso people who live in Southern Ethiopia are relatively close to the site. They, like other Eastern Cushite speakers, still use these same stars for calendars, which works on a 12 “month” calendar of 354 days. This calendar, with complex calculations reflecting moon phases in certain parts of the sky, may well have been in use for about 7,000 years.


Early arguments about Stonehenge are, like the pyramids, solar. Division of year into seasons may have been crucial, and sun’s movement seems to have had some relevance here, although the appearance of different stars throughout the year is also a good marker (viz. heliacal rising). ONE PROBLEM IS DATING. These are in some dispute:

Some debate about age of Stonehenge, although all agree it predates the Druids who were in England at the time of the Romans. Generally Stonehenge is believed to have been built and modified over a rather substantial period of time, divided into three periods.

North claims between 3000 and 3500 BC the monument began; Krupp argues for 2,800 BC.

North argues for a date of 1700 B.C. for the final phase; Krupp for about 1550 BC

Hawkins dates the whole thing 1900-1600 BC

Period I (2800 BC): Site enclosed with a circular ditch and an internal bank with an entrance on the NE side. A set of 56 pits arranged in a ring on the inner side of the ditch, called the Aubrey holes after their 17th cent. discoverer, are also of this period. Cremated bodies (from a later period) were placed in these holes. Outside the entrance the builders erected the “Heelstone” and a timber gate.

Period II (2100 BC) people of the Beaker culture built an earthenwork approach road, now called the AVENUE to the entrance of the bank and ditch. They also set up within the existing ring, a double circle of bluestone MENHIRS (large rough hewn standing stones) from southwestern Wales. BOTH THE AVENUE AND DOUBLE CIRCLE WERE ORIENTED TO THE SUMMER SOLSTICE SUNRISE.

PERIOD III (2000 BC) 30 Sarsen stones (uprights) capped with lintels forming a 100 ft. diameter circle enclosing a horseshoe shaped setting of five sarsen trilithons (3 stones) which come from Marlborough Downs.

Period IV Avenue extended to the Avon River (2K from Stonehenge).

Seem to be a large number of stellar alignments.

Also MOON alignments:

Greatest standstill
Least standstill

Also SUN alignments

Some not so concerned with actual dates, but with appearance of certain events.

Solstices, equinoxes. These divide the year into 4 parts (marked in bold below) which may be a bit too unmanageable. Halve those times (marked in italics below)and the year is divided into eighths.

Solstice (winter) Dec 21

Candlemas, Groundhog, Imbolg Feb. 1

Equinox (vernal) March 21

May Day (Beltine)(Walpurgis Nacht 4/30) May 5

Solstice (Summer) June 21

Lammas (Lugnasad) August 6

Equinox (autumnal) Sept. 21

Martinmas, Samhain, (Halloween) Nov. 1

These dates are difficult to deal with, not only because of precession, but also because the earth's orbit is not quite circular, so the number of days between equinoxes are not quite equal. Between spring and fall equinox there are 187 days; between fall and spring, there are 178.

Stonehenge and other Megalithic Monuments often show "errors" which actually are not, if you deal with days rather than actual equinoxes (that is count days, not use actual equinoxes). This would lead to Calendric equinox to be a little later in spring, and a little earlier in the fall. Calendric alignments on sunrises would be set a bit north of east and this is what Thom finds.


Callinish (Scottish Stonehenge)

Eleven Shearers (S.E. Scotland)

Learable Hill (Between Caithness and Sutherland, Scotland)

Long Meg and Her Daughters (Cumbria, England)

Namoratunga II (Kenya) (300 B.C.)

Newgrange (Ireland)

Stonehenge (Salisbury Plain, England)

Many of these have stones which show common alignments: Solstices, Equinoxes etc.

Stones seem to mark astronomical events as well as the marking of sacred space. The question is one of alignment. Many stones lead to many possibilities.


There are ways of getting Stonehenge to calculate lunar eclipses. The big problem is that they would not have all been visible from Stonehenge or even England.

One suggestion is that they could predict moments when an eclipse MIGHT happen, hence it was a time of danger. Still not clear how anyone would have know this.