NATS 1745Lecture 1 & 2
Archaeoastronomy and the Sun:
3 SitesNewrange (Ireland), Sundagger (Mexico), Stonehenge (Southwest England)
1.Newrange (3200 BC):
a) Newranges roofbox is aligned to the winter solstice sunrise.
• The oldest roof structure
• Over 5000 years old
• Simple solar connection
b) The alignment of the tomb likely reflects a belief in rebirth of reincarnation.
2.The Sundagger of Chaco Canyon (1000 AD)
a) On the summit of Fajada Butte in New Mexico, 2 spiral carvings were found
behind 3 stone slabs.
• 1000 years old
• Over 600 rooms
• Very important huge residence, or business res, or worshipping center
• ASpring Equinox, B Summer Solstice, CFall Equinox, DWinter Solstice.
Mark how to predict the annual path of the sun
b) At noon on the solstices and equinoxes, the Sundagger exhibits 2 beams of
sunlight, which either bisect or frame the spirals.
3. Stonehenge (2200 BC)
a) Stonehenge’s Heel Stone is aligned to the summer solstice sunrise.
• Constructed in stages in 2200 BC, could have been used in 3000 BC
• Stonehenge’s heel stone is aligned to the summer solstice sunrise
• Also connection to solar or moon eclipse and the moon itself
• Thought to have healing powermany skeleton remains to have injury
b) Today, the summer solstice Sun rises behind the Heel Stone
c) When Stonehenge was built, the summer solstice Sun rose beside the Heel
Stone (due to the precession of the equinoxes).
• Popular theory was originally a second stone astronomical evidence, the
precise location shifts every year very little and over years they just moved
it once to the left.
d) This suggests: there used to be 2 Heel Stones to frame the sunrise.
NATS 1745Lecture 2 The Sun’s Daily Cycle
1. Due to Earth’s 24hour eastwardspin around its polar axis, the Sun moves
westward across the sky; it rises in the east, reaches its highest point at noon, and
then sets in the west.
• The Sun turns westerly, it rises in the east and sets in the west
2. NHemisphere: Sun is mostly seen on the South side of the sky, reaching due
South at noon
• A person must face North to see the Sun
3. SHemisphere: Sun is mostly seen on the North side of the sky, reaching due
North at noon.
• A person must face South to see the Sun
Local noon: when your location is facing the Sun.
Local midnight: when your location is facing the opposite side of the sky from the
Local sunrise or sunset: when the Sun’s direction is perpendicular to your
The Sun’s Annual Cycle
1. Fall and Spring Equinox (Sept 23, March 21): Sun rises due to E and sets due W,
spending equal time above and below the horizon (equal day and night).
(Equinox: Latin for “equal night”).
2. Winter Solstice (Dec 22): Sun rises and sets at its southernmost position,
traversing a short, low arc in the sky (shortest day of the year and lowest noon
sun). (Solstice: Latin for “solar standstill”).
3. Summer Solstice (Jun 22): Sun rises and sets at its northernmost position,
traversing a long, high arc (longest, highest noon sun).
4. In the Shemisphere, the Sun’s daily arcs point N rather than S.
5. Identifying the Sun’s rising and setting positions on the solstices simply requires
finding its nethermost and southernmost positions.
6. The seasonal changes in the Sun’s daily arc are due to Earth’s 23.5 degree tilt
from its orbit around the sun.
7. Winter: When a hemisphere is tilted away from the Sun, sunlight hits indirectly
(EX: at and angl