FOR DISCUSSION TODAY: THE ANNUAL MOTION OF THE SUN

ANNOUNCEMENTS Homework #1 due today at end of class. HW #2 due next Thursday. Homework #1 question #1 and Homework #2 meridian slice questions will be discussed in the course of the lecture today. Observing Projects. Make sure you understand what is required. Help for Projects as follows: Kate Vann (Sundial, Lunar Phases & Lunar Eclipse); Bobby Wallace (Astrology, Horizon Calendar & Eratosthenes); John Stocke (Constellations, Skygazer & Lunar Eclipse). Watch for announcement of Sundial and Eratosthenes help sessions early next week. LUNAR ECLIPSE: SUN SEPT 27 th 6:30pm UP FOR DISCUSSION TODAY: THE ANNUAL MOTION OF THE SUN

TIME OF DAY AND DATE OF YEAR MOTION OF SUN ACROSS SKY DEFINES THE HOURS; NOON WHEN SUN CROSSES THE MERIDIAN. ONE DAY OF 24 HOURS IS TIME BETWEEN SUCCESSIVE MERIDIAN CROSSINGS (IN 24 HOURS EARTH TURNS THROUGH ALL CELESTIAL LONGITUDES) MOTION OF SUN THROUGH FULL CYCLE OF ITS CELESTIAL LATITUDES (DECLINATIONS) DEFINES THE YEAR. THE TROPICAL YEAR IS THE NUMBER OF DAYS (365¼ - a bit) BETWEEN SUCCESSIVE CROSSING OF THE CELESTIAL EQUATOR GOING NORTHWARDS (CALLED THE VERNAL OR SPRING EQUINOX). i.e., SPRING TO NEXT SPRING

UNLIKE THE FIXED STARS, THE SUN CHANGES ITS CELESTIAL LATITIUDE. THE CHANGING AMOUNT OF SOLAR HEATING AT ANY ONE MOMENT AND THE CHANGING NUMBER OF HOURS AND MINUTES OF DAYLIGHT DETERMINE THE SEASONS.

Sun higher in sky Greater heat per square foot SUMMER Sun lower in sky Less heat per square foot WINTER At Equinoxes the Poles of the Earth are pointed in space perpendicular to the direction to the Sun FILM: A PRIVATE UNIVERSE Sun is over the equator and intermediate between Solstices

AT MID-LATITUDES: calendars set by SUN ON HORIZON OR SUN ON MERIDIAN AT LOW LATITUDES (i.e., in the TROPICS) THE SUN S HORIZON LOCATION CHANGES LESS AND ALTITUDE ALONG MERIDIAN CHANGES VERY LITTLE

THE FOUR CORNERS OF THE YEAR : SOLSTICES AND EQUINOXES MARCH 20 OR 21 st : SPRING OR VERNAL EQUINOX ( EQUAL NIGHT TO DAY ) JUNE 21 ST : SUMMER SOLSTICE OR MIDSUMMER {solstice means Sun standing still (on horizon as it sets)} SEPTEMBER 21 st OR 22 nd : FALL EQUINOX DECEMBER 21 st : WINTER SOLSTICE SOLSTICES: SUN IS AS FAR NORTH OR AS FAR SOUTH AS SUN CAN GET: CELESTIAL LATITUDE = + 23½ o AND 23 ½ o. EQUINOXES: SUN IS ON THE CELESTIAL EQUATOR (Celestial latitude = 0). DAY & NIGHT OF EQUAL LENGTH OF TIME. LATITUDE =+23½ O IS CALLED THE TROPIC OF CANCER and LATITUDE =-23½ O IS CALLED THE TROPIC OF CAPRICORN IN BETWEEN THESE LATITUDES ARE THE TROPICS.

THE MERIDIAN SLICE Has the Celestial Latitude = terrestrial latitude @ the zenith Basis of celestial navigation to determine one s LATITUDE. Measure the altitude of the meridian passage of fixed stars; i.e., fixed celestial latitudes *** WHERE ARE THE SOLAR ZONES FOR KEY WEST & THE EQUATOR?

THE MERIDIAN SLICE Has the Celestial Latitude = terrestrial latitude @ the zenith Basis of celestial navigation to determine one s LATITUDE. Measure the altitude of the meridian passage of fixed stars; i.e., fixed celestial latitudes

THE SOLAR ZONE: AT ANY ONE LOCATION THIS IS THE FULL RANGE OF LOCATIONS ALONG THE MERIDIAN WHERE THE SUN CAN BE SEEN DURING THE YEAR. IN EITHER HEMISPHERE WHICH OF THE ABOVE LOCATIONS ARE IN THE TROPICS? THE SOLAR ZONE LOCATES THE SUMMER (HIGHEST ALTITUDE EDGE OF SOLAR ZONE) AND WINTER SOLSTICES. THE EQUINOX POSITIONS ARE HALFWAY BETWEEN THESE TWO EXTREMES.

HORIZON CALENDAR: requires both a foresight (typically point on horizon) and backsight (location or stone marker) { see Observing Project #2} HOPI of ARIZONA USE A HORIZON, SUNSET CALENDAR TO SET THEIR WINTER SOLSTICE CEREMONY THE SOYAL.

FORESIGHTS AND BACKSIGHTS: For the Hopi the foresight are points along the mountain horizon; the backsight a specific location in Walpi, First Mesa of the Hopi.

CELESTIAL LATITUDE OF THE SUN THROUGH THE YEAR SOLSTICES AND EQUINOXES IN GREEN CONTINUES RED MARKS SHOW APPROXIMATE LOCATIONS OF CROSS-QUARTER DAYS NOTE TWO SUNS PHENOMENON: SUN STAYS CLOSE TO SAME LOCATION IN SKY OVER MOST OF YEAR: SUMMER SUN AND WINTER SUN

CELESTIAL LATITUDE OF SUN THROUGH THE YEAR SOLSTICES AND EQUINOXES IN GREEN RED MARKS SHOW APPROXIMATE LOCATIONS OF CROSS-QUARTER DAYS NOTE TWO SUNS PHENOMENON: SUN STAYS CLOSE TO SAME LOCATION IN SKY OVER MUCH OF YEAR: SUMMER SUN AND WINTER SUN Time of changes SUMMER SUN Winter Sun Winter Sun CONTINUES

COLOSSI OF MEMNON TEMPLE OF AMENHOTEP III AT THEBES (1350 BCE 1200 YEARS AFTER PYRAMIDS) ALIGNED WITH WINTER SOLSTICE SUNRISE!!

TEMPLE OF AMENHOTEP III C. 1350 BCE (1200 YEARS AFTER THE GREAT PYRAMIDS AT GIZA SUN WORSHIP REPLACED OSIRIS BITRTH/DEATH/ REBIRTH CULT SOLAR COURTYARD ILLUMINATED ONLY AT WINTER SOLSTICE DAWN!

NEWGRANGE IN IRELAND A 5000+ YEAR OLD PASSAGE TOMB ALIGNED TO WINTER SOLSTICE SUNRISE ONLY AT THE WINTER SOLSTICE SUNRISE IS THE INNERMOST CHAMBER OF THIS PASSAGE TOMB ILLUMINATED BY THE SUN. An obvious symbol of rebirth, of the year and so of humans.

STONEHENGE: EARLIEST ASTRONOMICAL CONSTRUCTION C. 3200 BCE.

WINTER SOLSTICE SUNSET

QUESTION: WHY WOULD THE WINTER SOLSTICE BE THE ONE WHICH IS MOST CELEBRATED BY ANCIENT PEOPLES? 1. IT MARKS THE RETURN OF THE LIGHT 2. LESS DAYLIGHT FOR WORKING, MORE TIME FOR PARTYING. 3. IT S A SILLY, PAGAN THING. 4. AT THE WINTER SOLSTICE, THE DARKNESS OVERWHELMS THE LIGHT. IT S AN EVIL TIME. 5. SOME ANCIENT PEOPLES WERE WORRIED THAT THE SUN WOULD KEEP GOING SOUTH AND STAY THERE.

QUESTION: WHY WOULD THE WINTER SOLSTICE BE THE ONE WHICH IS MOST CELEBRATED BY ANCIENT PEOPLES? 1. IT MARKS THE RETURN OF THE LIGHT 2. LESS DAYLIGHT FOR WORKING, MORE TIME FOR PARTYING 3. IT S A SILLY, PAGAN THING. IN THE OLD ROMAN CALENDAR THE WINTER SOLSTICE WAS ON DECEMBER 25 th AND WAS CALLED THE DAY OF THE UNCONQUERABLE SUN! CHRISTIANS CO- OPTED IT. 4. AT THE WINTER SOLSTICE, THE DARKNESS OVERWHELMS THE LIGHT. IT S AN EVIL TIME. 5. MANY ANCIENT PEOPLES WERE WORRIED THAT THE SUN

ANCIENT TRADITION IS THAT FIRST DAYS OF SEASONS ARE THE CROSS QUARTER DAYS.. e.g., BELTANE (May Day) is the first day of summer. June 21 st, the Summer Solstice is also called High or Mid-Summer.

We ll take these one-by-one. ALL WERE USED BY ANCIENT PEOPLE BUT TRADITION DIFFERED IN DIFFERENT LOCATIONS AND CULTURES.

OLDEST KNOWN SOLSTICE MARKERS IN THE WORLD: CIRCA 5000 BCE IN SOUTHERN EGYPT. Site mapped by CU Professor Emeritus Kim Malville. ** SHOW VIDEO: COSMIC AFRICA **

BABYLONIAN/GREEK SOLUTION WAS TO KEEP BOTH SUN AND MOON CYCLES AND INTER- CALATE BY ADDING AN ENTIRE 13 TH MONTH ON A SCHEDULE OVER 19 YEARS. EGYPTIAN SOLUTION WAS TO ABANDON LUNAR CYCLE ALTOGETHER SO THAT THE YEAR WAS ALWAYS THE SAME NUMBER OF DAYS (365) AND MONTHS (12) BUT MONTHS HAD > 29 0R 30 DAYS.

WHEN ROME BECAME THE POLITICAL AND MILITARY POWER IN EUROPE THE LUNAR CYCLE WAS ABANDONED IN FAVOR OF THE EGYPTIAN SOLAR CALENDAR.

BY 1600s THE CLERGY NOTICED THAT EASTER WAS SLOWLY BECOMING A WARM-WEATHER SUMMERTIME FESTIVAL, NOT THE SPRING REBIRTH SYMBOLICALLY REQUIRED POPE GREGORY WAS CONVINCED TO CHANGE THE CALENDAR AND HE GOT CATHOLIC COUNTRIES TO CHANGE BUT NOT THE PROTESTANT ONES e.g., BRITAIN DID NOT CHANGE UNTIL 1700s.; Russia in 1900s.