SOAR: The Sky in Motion y Life on the Tilted Teacup Ride Phases of the Moon Aileen A. O Donoghue Priest Associate Professor of Physics
Kiva December 1997 October 27, 2009
Celestial Coordinates Right Ascension RA or α From prime meridian (0 h ) to 23 h 59 m 59 s Eastward NCP Declination Dec or δ From celestial equator (0º) to poles N & S 90º SCP
Tilted Sky Observers see sky tilted due to latitude We see ourselves on top of the Earth, beneath the sky. To NCP To NCP Zenith To Celestial Equator So we see sky motions tilted Observer s Latitude λ
Clock Time = Position of Sol Observers move through h times It s 9 pm. It s 6 pm (sunset). It s 3 pm. It s midnight. It s noon. It s 3 am. It s 9 am. It s 6 am (sunrise).
Sun in the sky View from Earth Rotate to Earth s equatorial plane Center on Earth Project sun onto sky The Ecliptic NCP Vernal Equinox SCP
The Ecliptic (path of the sun) View from Earth Sun moves ~1º/day eastward across stars Sun moves north and south in declination i Solstices & Equinoxes are positions in the sky. This motion is through the YEAR!
View from Earth Sun in the sky Sun moves ~1º/day eastward across stars Sun moves north and south in declination 18 h, 12 h, 6 h, 0 h, 23.5º Celestial Equator 0º +23.5º 0º Winter Solstice in Sagittarius Autumnal Equinox in Virgo Summer Solstice in Taurus Vernal Equinox in Pisces
Position of Sunrise & Sunset Azimuth of rising i depends d on δ sinδ = cosλ In Potsdam (44 40 N 75 59 W) 1 Arise cos degrees Summer: Winter: 1 sin 23.5 A = cos = 55.9 degrees rise cos 44.67 1 sin -23.5 A = cos = 124.1 degrees rise cos 44.67 68.2
Position of Sunrise & Sunset Sun rises at 56 in Summer, 124 in Winter North Summer 292 0 30 56 Summer 45 NE 60 68.2 90 East 68.2 120 Winter 236 124 South 180 Winter
When on Earth? Earth Rotates Once Each Day 360 with respect to Earth-Sun line All Earthlings ride along To Sol
Observers move through times Clock Time 6 pm 9 pm 3 pm 12 am 12 pm 3 am 9 am 6 am
Moon orbits Earth Solar Month New Moon to New Moon 29d 12h 44m ~ 29.5d Sidereal Month Moon moves 360 27d 7h 43m Moon rotates on its axis once/month Keeps same face toward Earth hangs heavy side down Appears larger at perigee than apogee
Moon orbits Earth Lunar Month New Moon to New Moon 29d 12h 44m ~ 29.5d
Moon Phase is lit moon visible Insert is moon as see from Earth
Moon Phases New Moon: Elongation = 0 (angle from sun to moon) Waxing Phases: visible after sunset Waxing Crescent: 0 < Elongation < 90 E First Quarter: Elongation = 90 E Waxing Gibbous: 90 E < Elongation < 180 Full Moon: Elongation = 180 1 st QUARTER transit WAXING GIBBOUS eastern sky Observer s meridian WAXING CRESCENT western sky FULL rising south Elongation = Angle from Sun NEW setting SUN SETTING
Evening Moon Phases Look south at sunset 9/28/6 6:47:00 pm Waxing Gibbous 11/18/9 11/19/9 11/20/9 11/21/9 11/22/9 11/23/9 11/24/9 11/25/9 11/26/9 11/27/9 11/28/9 11/29/9 11/30/9 12/01/9 4:29:55 4:29:05 4:27:29 4:21:53 4:26:45 4:26:03 4:25:23 4:24:46 4:24:11 4:23:38 4:23:09 4:28:16 4:22:41 4:22:15 pm Almost First Waxing Quarter Full Crescent Gibbous
Evening Moon Phases Look south at sunset 9/28/6 6:47:00 pm Waxing Gibbous 11/18/9 11/19/9 11/20/9 11/21/9 11/22/9 11/23/9 11/24/9 11/25/9 11/26/9 11/27/9 11/28/9 11/29/9 11/30/9 12/01/9 4:29:55 4:29:05 4:27:29 4:21:53 4:26:45 4:26:03 4:25:23 4:24:46 4:24:11 4:23:38 4:23:09 4:28:16 4:22:41 4:22:15 pm Almost First Waxing Quarter Full Crescent Gibbous
Moon Phases Full Moon: Elongation = 180 Waning Phases: visible before sunrise Waning ng Gibbous: 90 W < Elongation < 180 Third Quarter: Elongation = 90 W Waning Crescent: 0 < Elongation < 90 W New Moon: Elongation = 0 3 rd QUARTER transit WANING CRESCENT eastern sky Observer s meridian WANING GIBBOUS western sky SUN RISING NEW rising Elongation = Angle from Sun south Full setting
Morning Moon Phases Look south at sunrise the cold moon 12/02/6 5:00:00 am Full Moon
Morning Moon Phases Look south at sunrise 12/02/9 12/03/9 12/04/9 12/05/9 12/06/9 12/07/9 12/08/9 12/09/9 12/10/9 12/11/9 12/12/9 12/13/9 12/14/9 12/15/9 7:27:35 7:26:42 7:28:26 7:30:02 7:30:46 7:29:15 7:19:47 7:21:53 7:22:55 7:23:54 7:24:52 7:25:48 7:18:41 7:20:51 am Full Third Waning Moon Quarter Crescent Gibbous
Morning Moon Phases Look south at sunrise 12/02/9 12/03/9 12/04/9 12/05/9 12/06/9 12/07/9 12/08/9 12/09/9 12/10/9 12/11/9 12/12/9 12/13/9 12/14/9 12/15/9 7:27:35 7:26:42 7:28:26 7:30:02 7:30:46 7:29:15 7:19:47 7:21:53 7:22:55 7:23:54 7:24:52 7:25:48 7:18:41 7:20:51 am Full Third Waning Moon Quarter Crescent Gibbous
Moon Phases & Time of Day Moon phase Due to positions of Earth, Sun & Moon Time of Day Due to positions of Earth, Sun & Observer Position & Phase of Moon Gives Time of Day
Earth rotates beneath each phase Example: First Quarter
Single observer sees moon in sky Observer sees moon rising
Single observer sees moon in sky Observer sees moon in eastern sky
Single observer sees moon in sky Observer sees moon transiting as sun sets
Single observer sees moon in sky Observer sees moon in western sky
Single observer sees moon in sky Observer sees moon setting
Earth rotates beneath each phase Example: First Quarter
Earth Observer Observer views moon from own horizon system
Earth Observer Observer only aware of own horizon system
1 st Quarter Observer Light from the sun
Waning Gibbous Observer Light from the sun
Phases Rising & Setting 1 st Quarter Rises at noon Sets at midnight waxing gibbous 1 st quarter 90 6pm waxing crescent eastern elongations ns Waning Gibbous Rises at 9 pm waning Sets at 9 am full 180 gibbous mdnt noon Earth 180 0 6am 90 western elongations waning crescent new 3 rd quarter
Today s Fun Determine rising, i transit and setting times of each phase Time is the one above the observer s head! full waxing gibbous 9pm Observer s Time Above mdnt Rising Moon to East Transiting Moon Above 1 st quarter 6pm Setting Moon to West Earth rotation 3pm waxing crescent noon new waning gibbous 3am 6am 9am waning crescent 3 rd quarter
Phases & Times What s the phase of the moon that rises at 3 am? waxing gibbous 9pm 1 st quarter 6pm 3pm waxing crescent 3 am is the OBSERVER S TIME! full mdnt Earth rotation noon new No other times matter! Rising moon on eastern horizon No other phases matter! waning gibbous 3am Observer s Time Above 6am Rising 9am Moon to East waning crescent 3 rd quarter
Phases & Times What time does the phase rise & transit Turn observer through h day Find time for transit Find time for setting mdnt 9pm 3am Rising Time 6pm 6am 3pm 9am Setting Time noon Transit Time waning crescent Waning Crescent rises at 3 am, transits at 9 am, sets at 3 pm
Now show the diagram 1 st Quarter Rises at noon Transits at 6 pm Sets at midnight waxing gibbous At midnight, moon s Setting in the West 1 st quarter 90 6pm full 180 mdnt noon 0 At 6 pm, moon is Transiting in the southern sky waxing crescent It s noon and the moon is Rising in 0 the East new 6am 90 waning gibbous waning crescent 3 rd quarter
Now show the diagram Waning Gibbous Rises at 9 pm Transits at 3 am Sets at 9 am At 3 am, moon s transiting in the southern sky waxing gibbous At 9 pm, moon s Rising in the East full 180 waning gibbous 1 st quarter 90 6pm 180 mdnt noon 0 6am 90 waxing crescent It s ts9a am,,the moon s Setting in the West waning crescent new 3 rd quarter
Question An observer sees the full moon transit. What time is it? a) 6 pm b) Midnight c) 6 am full waxing gibbous 9pm Transiting Moon Above mdnt Observer s Time Above waning gibbous 3am 1 st quarter 6pm 6am 3pm 9am waxing crescent noon waning crescent new 3 rd quarter
Question An observer sees the moon rise at 9 am. What phase is it? waxing gibbous 9pm 1 st quarter 6pm 3pm Rising Moon to East waxing crescent full a) Waning Gibbous b) Waning Crescent c) Waxing Crescent mdnt waning gibbous 3am 6am noon new Observer s Time Above 9am waning crescent 3 rd quarter
Question An observer sees the moon set at 6 pm. What phase is it? waxing gibbous 9pm 1 st quarter 6pm Observer s Time Above 3pm Setting Moon to West waxing crescent a) New Moon b) First Quarter c) Full Moon full mdnt waning gibbous 3am 6am 9am noon waning crescent new 3 rd quarter
Question An observer sees the waxing crescent moon rise. What time is it? waxing gibbous 9pm 1 st quarter 6pm 3pm Rising Moon on eastern horizon waxing crescent full mdnt noon new a) 9am b) 3 pm c) 9 pm waning gibbous 3am 6am Observer s Time Above 9am waning crescent 3 rd quarter
Harvest Moon 2009 Some full moons are named harvest moon = full moon closest to equinox October 4, 2:11 am Moon bright at rising for days Allowed farmers to work into the night hunter s moon = follows harvest moon November 2, 2:14 pm
10/1/9 10/2/9 10/3/9 10/4/9 10/5/9 Harvest Moon 2009 Some full moons are named harvest moon = full moon closest to equinox October 4, 2:11 am Moon bright at rising for days hunter s moon = follows harvest moon November 2, 2:14 pm