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Home , Lunar node, Lunar standstill

ANNOUNCEMENTS . HOMEWORKS #4 & #5 handed out today. HAND HW#4 IN FOR CREDIT NEXT THURSDAY

. IF YOU WISH HAND-in #5 NEXT THURS TO REPLACE POOREST GRADE ON PREVIOUS HWs . Material from BOTH HWs will be covered on the Midterm Exam

. Midterm exam 1.5 from today in TUESDAY’S class on OCTOBER 13th in BESC 180.

. OPTIONAL Observing at SBO next Monday 7:30pm.

. OPTIONAL “ERATOSTHENES CHALLENGE” HELP SESSION next Monday 2—4 pm or next Tuesday 3:30-5pm @ GATE #5 Folsom Field

. OPTIONAL Dark Sky Field Trip next Tuesday 6:15pm meet at Fiske…dress very warmly. Pray for clear weather.

Eclipse video with possibly offensive language (my mother would have been offended; my son would not) will be shown in first 10 minutes of class period on Tuesday. Come late if you wish. For how long have Humans had the ability to predict of the and the ?

Could all eclipses have been predicted in ancient times? The Battle of Halys took place at the river Halys in Turkey) on May 28, 585 BCE between the Medes and the Lydians.

A Solar occurred, was viewed as an omen from the gods and the war was ended!

First known prediction by Thales of Miletus….HOW DID HE DO IT???

Subsequently the Lydians and the Medes drew up peace accords.

Only a few dozen Solar Eclipses are mentioned throughout antiquity…these events are RARE in any portion of the world.

AND YET ANCIENT PEOPLE KNEW HOW TO PREDICT ECLIPSES !!!

*** this is why I want you to know what appears to be obscure details of the lunar orbit called LUNAR STANDSTILLS *** BECAUSE IS ALWAYS NEARLY EXACTLY OPPOSITE TO THE SUN (FULL MOON RISES WHEN SUN SETS) IT ALSO SWINGS NORTH AND SOUTH DURING THE …BUT OPPOSITE TO THE SUN’S SWING: e.g., THE MIDWINTER FULL MOON IS THE HIGHEST IN THE SKY, RISES AND SETS FURTHEST NORTH OF EAST AND WEST & IS UP THE LONGEST !! BEAUTIFUL. ECLIPSE : TWICE PER YEAR WHEN SUN IS NEAR THE LOCATION OF ONE OF THE TWO NODES

Moon’s path

 NODE’S PATH

ECLIPSE SEASONS WOULD ALWAYS BE AT SAME TIME OF YEAR…except LUNAR ORBIT “TWISTS” IN SPACE MOVING NODES BACKWARDS (19 DAYS PER YEAR!!) Lunar Orbit not stable. Nodes & standstill Why would we care about points move through the zodiac backwards these Standstill points?

 Nodes are where eclipses occur

 Nodes are invisible and cannot be directly observed or tracked.

 Standstills are 90 degrees away from the nodes.

 In the year of a eclipses happen close to the equinoxes.

 Eclipse prediction ! EXTREMES OF THE LUNAR ORBIT

Because the Moon’s orbit is titled with respect to the plane, the Moon sometimes gets up to 5 degrees NORTH of the ecliptic or up to 5 degrees SOUTH of the ecliptic.

But for the Full Moon these extremes happen only once every 9.5 (a northern extreme in winter is followed 9½ years later by a southern extreme for the Full Moon nearest the summer ).  FULL CYCLE OF STANDSTILLS IS 19 YEARS (closest even number to the 18 and two-thirds year cycle of the nodes.

These extremes are called: MAJOR LUNAR STANDSTILLS IN ANALOGY WITH , EXTREME LOCATIONS OF THE SUN. Eclipse at solstices

NOTE WELL: THE ABOVE SKETCH IS QUITE SMALL IN COMPARISON TO THE SKETCHES AT LEFT. THE FULL EXTENT ABOVE IS ONLY A BIT OVER TWO THUMB LENGTHS IN THE SKY !!!

AN ECLIPSE HAPPENS AT THE FULL MOON CLOSEST TO THE SOLSTICE IN THE YEAR DEPICTED AT CENTER ABOVE. OTHER YEARS “ECLIPSE SEASONS” ARE AT OTHER TIMES NOTE WELL: THE ABOVE SKETCH IS QUITE SMALL IN COMPARISON TO THE SKETCHES AT LEFT. THE FULL EXTENT ABOVE IS ONLY A BIT OVER TWO THUMB LENGTHS IN THE SKY !!!

AN ECLIPSE HAPPENS AT THE FULL MOON CLOSEST TO THE SOLSTICE IN THE YEAR DEPICTED AT CENTER ABOVE. OTHER YEARS “ECLIPSES SEASONS ARE AT OTHER TIMES NOTE WELL: THE ABOVE SKETCH IS QUITE SMALL IN COMPARISON TO THE SKETCHES AT LEFT. THE FULL EXTENT ABOVE IS ONLY A BIT OVER TWO THUMB LENGTHS IN THE SKY !!!

AN ECLIPSE HAPPENS AT THE FULL MOON CLOSEST TO THE SOLSTICE IN THE YEAR DEPICTED AT CENTER ABOVE. OTHER YEARS “ECLIPSES SEASONS ARE AT OTHER TIMES AT SOLID LINE IN CENTER, FULL MOON IS ON THE ECLIPTIC AND AN ECLIPSE OCCURS,

ONCE EVERY 9 YEARS A OCCURS on THE FULL MOON NEAREST THE SOLSTICE

 FULL CYCLE OVER A 18 ½ - 19 YEAR PERIOD next one: June 2025 last one: early July 2015 AT SOLID LINE IN CENTER, FULL MOON IS ON THE ECLIPTIC AND AN ECLIPSE OCCURS,

 ONCE EVERY 9 ½ YEARS A LUNAR ECLIPSE SEASONS ECLIPSE OCCURS on NEAR SOLSTICES THE FULL MOON NEAREST THE SOLSTICE

ECLIPSE SEASONS ECLIPSE SEASONS NEAR EQUINOXES NEAR EQUINOXES ECLIPSES POSSIBLE ONLY TWICE PER YEAR DURING “ECLIPSE SEASONS” WHEN FULL & NEW OCCUR CLOSE TO THE NODES

In the year of a lunar standstill (either “major” or “minor”), the Eclipse Seasons are near the equinoxes ECLIPSE NUMEROLOGY: AN INTRODUCTION

ECLIPSE “SEASONS”: The possibility for one or more eclipses happens twice per year when Full and/or occurs in or near the Lunar Nodes.

Because nodes move “backwards” around the Moon’s orbit, these eclipse seasons are LESS THAN ½ year apart: 173 DAYS to be exact.

ECLIPSE SEASONS MOVE “BACKWARDS” through the calendar at a pace of about 19 days per year…eclipse seasons are ~ 19 days earlier than the previous year.

ECLIPSE SEASONS CYCLE THROUGH THE CALENDAR ONCE EVERY 9 ½ YEARS…or TWICE IN 19 YEARS (“YEAR OF METON”) NOTICE AT LEFT PROGRESSION OF SPRING :

1984 end of May

1985 beginning and mid May

1986 mid April

1987 late March

1988 mid March (year of a lunar standstill) STONEHENGE: TEMPLE OR OBSERVATORY ? EARLIEST CONSTRUCTION c. 3200 BCE STONEHENGE:

A MONUMENT CONSTRUCTED IN STONE AGE BRITAIN STONEHENGE BUT BY WHOM AND WHY ???

90 MILES SW OF LONDON ON SALISBURY PLAIN AT THE INTERSECTION OF 2 HIGHWAYS.

SURROUNDED BY BARROW DOWNS (ANCIENT GRAVES) INTERESTINGLY THERE WERE SEVERAL BUILDING PERIODS AT THIS SITE…. LATEST DATES SUGGEST circa 3200 BCE STONEHENGE 1 WAS “ERECTED” PRIOR TO 3000 BCE, OVER 5000 YEARS AGO! circa 2500 BCE STONEHENGE 1 MORE INTERESTING ASTRONOMICALLY… Circa 2400 BCE STONEHENGE 3 MORE INTERESTING FOR ITS ENGINEERING.

THE “HEELSTONE”

SUMMER SOLSTICE SUNRISE “BACKSIGHT”

FORESIGHT AT CENTER OF SARCEN CIRCLE STONEHENGE 1 STONEHENGE 2 & 3 (c. 3200 BCE) (c. 2400 BCE)

“AVENUE” + DITCH MASSIVE STONES including 56 HOLES FILLED WITH CHALK 5 “TRI-LITHONS” , “SARSEN FEW LOCAL STONES CIRCLE” & BLUESTONES ONE OF 56 EVENLY SPACED AROUND 3OO FOOT DIAMETER CIRCLE

THE EVIDENCE FOR ECLIPSE REASONS WHY STONEHENGE 1 PREDICTION IS WAS LIKELY AN ECLIPSE CIRCUMSTANTIAL but PREDICTOR: RELIES ON: 1. 56 AUBREY HOLES: 56 = 18 2/3 X 3 (three times the period of the nodes). The NUMEROLOGY: NUMBER 56 Classical World’s “Year of Meton” RELATED TO 2. Stonehenge 3 “Rectangle” accurately CYCLE AND HAS NO OTHER aligned with solstices and standstills to ± ½ OBVIOUS CYCLES OR USE degree. Stonehenge 1 circle is larger and so accuracy is better: ± ¼ degree ! (size of GEOMETRY: ALIGNMENTS Sun and Moon in sky ≈ ½ degree  Stonehenge 1 accuracy good WITH EXTREME POSITIONS enough to predict all eclipses. OF BOTH THE SUN AND THE MOON  EXTREMES OF 3. Stonehenge Rectangle (summer MOON GIVE LOCATIONS OF solstice sunrise and full moon rise NODES ! at major standstill in perpendicular directions only within ± 150 miles of Stonehenge. THE STONEHENGE RECTANGLE

 Only at the of Stonehenge are the summer solstice sunrise point and the summer solstice Full Moon rise (at standstill) exactly perpendicular.

 Already present in  56 “Aubrey Holes” date to Stonehenge 1. (56 = 18 2/3 x Stonehenge 1.  3…exactly 3 times the cycle of the evidence for eclipse nodes) prediction c. 3000 BCE THEORIES ABOUT STONEHENGE CONTINUE TO ABOUND !!

NOTICE AT LEFT PROGRESSION OF SPRING ECLIPSE SEASON:

1984 end of May

1985 beginning and mid May

1986 mid April

1987 late March

1988 mid March (year of a lunar standstill) SHORT ECLIPSE SERIES IN BETWEEN “SKIPS” (NO ECLIPSE)