ANNOUNCEMENTS CLASS WEBSITE UP AND RUNNING @ http://casaweb.colorado.edu/astr2000/ Not D2L!! OPTIONAL OBSERVING SESSION TONIGHT AT SOMMERS-BAUSCH OBSERVATORY (SBO) AT 8:30pm (weather permitting!). I will send email by 8:00pm at latest IF ON/OFF. OFFICE HOURS: STOCKE: WED 1:30 2:30 PM AT PEKOE S COFFEE SHOP IN THE ATLAS BUILDING or BY APPOINTMENT WALLACE AND VANN: HOMEWORK CLUB WED 11AM-1PM & 4-6 PM IN DUANE ROOM D142 or BY APPOINTMENT. OPTIONAL DARK SKY OBSERVING TRIP: OCT 6 th ( RAIN DATE OCT 7 th ) TO THE CU MOUNTAIN RESEARCH STATION ANY STILL ON WAIT LIST CONTINUE COMING TO CLASS. 1 STILL ON WAIT LIST AT THIS TIME
Up for Discussion Today 1. DIURNAL (DAILY) MOTION OF THE SKY 2. COSMIC WHIRLPOOL AND THE 6 DIRECTIONS CIRCUM-POLAR STARS 3. ALIGNING THE PYRAMIDS 4. MOTIONS OF SKY AT DIFFERENT LATITUDES 5. THE MERIDIAN, CELESTIAL EQUATOR, AZIMUTHS, ALTITUDES, THE POLYNESIAN STAR COMPASS 6. INTRODUCTION TO A FEW CONSTELLATIONS
QUESTION HOW DO THE STARS APPEAR TO MOVE ACROSS THE SKY EACH NIGHT? 1. EAST TO WEST JUST LIKE THE SUN OR MOON 2. ALL MOVE DIFFERENT DIRECTIONS DEPENDING ON THEIR LOCATION IN THE SKY 3. ALL MOVE DIFFERENT SPEEDS DEPENDING ON THEIR DISTANCE FROM US 4. THE STARS STAY AT FIXED LOCATIONS ALL NIGHT LONG
ANCIENT PEOPLES DID NOT TAKE THE MOTIONS THEY SAW IN THE HEAVENS AS EVIDENCE THAT THE EARTH MOVES. If you could see stars in the daytime, this is what the sky would look like facing south at noon on a specific day in the summer. Ancients would say the Sun is in the zodiac constellation of Gemini. In what constellation would the Sun be at sunset that same day? Leo, Cancer, Gemini, Taurus, Aries, or Pisces?,
THE CELESTIAL SPHERE DAILY MOTION OF THE SKY.: GREEN LINE IS THE CELESTIAL EQUATOR WHEREON STARS RISE DUE EAST AND SET DUE WEST
What constellations would be visible in the sky after Sunset this day? If you could see stars in the daytime, this is what the sky would look like facing south at noon on a specific day in the summer. Ancients would say the Sun is in the zodiac constellation of Gemini. In what constellation would the Sun be at sunset that same day? Leo, Cancer, Gemini, Taurus, Aries, or Pisces?,
What constellations would be visible in the sky before Sunrise this day? If you could see stars in the daytime, this is what the sky would look like facing south at noon on a specific day in the summer. Ancients would say the Sun is in the zodiac constellation of Gemini. In what constellation would the Sun be at sunset that same day? Leo, Cancer, Gemini, Taurus, Aries, or Pisces?,
DAILY MOTION OF THE SKY. GREEN LINE IS THE CELESTIAL EQUATOR ON WHICH STARS RISE DUE EAST AND SET DUE WEST
ALTITUDE (OR ELEVATION) IS THE ANGLE UP FROM THE HORIZON.. Varies between 0 and 90 degrees.
AZIMUTH (OR BEARING) IS THE ANGLE ALONG THE HORIZON FROM NORTH THRU EAST.. Varies between 0 and 360 degrees.
THE RISING AND SETTING POINTS OF ALL STARS IS SYMMETRICAL AROUND THE MERIDIAN (NOT 180 O OPPOSITE). THIS IS ALSO TRUE FOR THE SUN, MOON AND PLANETS ON ANY GIVEN SINGLE DAY THESE RISING AND SETTING AZIMUTHS ARE FIXED AT ANY SPECIFIC LATITUDE
To make sure you get this: IF Mao Piailug sailed towards the rising point of Vega to get from his home island to a nearby island to get back home he sails: 1. Towards the setting point of Vega 2. Towards the rising point of Antares 3. Towards the North Star 4. Towards the Southern Cross 5. Towards the setting point of Antares 6. Away from the rising point of Vega 7. Away from the rising point of Antares
SOME STARS NEVER RISE OR SET: THESE ARE CALLED CIRCUM-POLAR STARS DAILY MOTION OF THE SKY. GREEN LINE IS THE CELESTIAL EQUATOR WHEREON STARS RISE DUE EAST AND SET DUE WEST
HOW ANCIENT PEOPLE ALIGNED THEIR STRUCTURES AND SO CAME INTO ORIENTATION WITH THE COSMOS? THEY USED THE COSMIC WHIRLPOOL.
FOR ANCIENT HUMANS THE MOTIONS VISIBLE IN THE SKY DEFINED THE VERY NATURE OF TIME AND INCREMENTS OF TIME DURING THE DAY: THE MOTION OF THE SUN AND ITS SHADOW DEFINED THE HOURS OF THE DAY. NOON IS THE TIME THAT THE SUN CROSSES THE MERIDIAN THE DAY IS THE TIME BETWEEN SUCCESSIVE NOONS AT NIGHT THERE WERE THE DECANS. STAR GROUPS THAT DEFINE THE NIGHTTIME HOURS BY THEIR SUCCESSIVE RISINGS, ONE AFTER ANOTHER.. THE TRADITION OF THE 24 HOUR DAY PROBABLY CAME FROM ANCIENT EGYPT BUT NO ONE KNOWS FOR SURE.
OBELISKS ARE GIANT SUNDIALS! OF THE 30 REMAINING EGYPTIAN OBELISKS: 7 ARE IN EGYPT AND ELEVEN ARE IN ROME!!!
EAST-TO-WEST MOTION OF STARS CAN BE USED TO TELL TIME AT NIGHT: THE EGYPTIAN DECANS Any one night has 12 hours One decan constellation is marked in a green box and marches across the 70 day calendar diagonally as it rises earlier and earlier each 10 days. NOTE: Big Dipper ( Bull s Thigh constellation at top!)
EAST-TO-WEST MOTION OF STARS CAN BE USED TO TELL TIME AT NIGHT: THE EGYPTIAN DECANS FORGOT TO SAY: THIS CALENDAR IS ON INSIDE OF AN OLD KINGDOM SARCOPHAGUS One decan constellation is marked in a green box and marches across the 70 day calendar diagonally as it rises earlier and earlier each 10 days. NOTE: Big Dipper ( Bull s Thigh constellation at top!)
DAILY MOTION OF THE SKY. GREEN LINE IS THE CELESTIAL EQUATOR WHEREON STARS RISE DUE EAST AND SET DUE WEST (slides)
UNITS OF TIME CREATED UNITS OF ANGLES IN THE SKY: Circa 2000 BCE Babylonians had a calendar of 360 days with 12 lunar months of 30 days. So they divided the circular path of the Sun and Moon through the sky into 360 degrees, one day for each day of the year The Sun moves ~ 1 degree each day through the stars. Because the Babylonians used a base 60 numbering system (we use a base 10 system), these degrees were divided into 60 parts and those parts into 60 parts. 1 degree = 60 arc-minutes & 1 arc-minute = 60 arc-seconds 1 arcminute resolution of human eye 1 arcsecond resolution of a ground-based telescope HORIZON TO ZENITH = 90 O (CALLED ALTITUDE) FULL CIRCUMFERENCE OF HORIZON = 360 O (CALLED AZIMUTH) BASE 60 COMES FROM BABYLONIANS
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