Simulated Lunar Phases The Moon s Phase = illuminated portion of the moon as seen from the Earth It takes 29.5 days to go through all the phases = one moooonth
Phases of the Moon new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, crescent and back to new phase
Phases Depend on Orbital Position Sun
When Will the Moon Rise?
Moon s Sidereal & Synodic Month Orbital period = 27.3 days = sidereal period From new moon to new moon = 29.5 days = synodic period = month
Sidereal and Solar Day Earth rotates once with respect to the stars in one Sidereal Day But Earth orbits the sun (revolves around) So it must rotate a little extra to point to the sun again for one Solar Day 4 minutes or 1 degree each day
When will the first quarter a) Sunset moon rise? b) Sunrise c) Noon d) Midnight e) Night time because the moon only comes out at night
Lunar Eclipse Movie Fred Espenak MrEclipse.com
Lunar Eclipse Geometry Umbra is dark part of shadow - no sun Penumbra is light part of shadow part of sun showing
Lunar Eclipse Animation Total Lunar Eclipse = Whole Moon in Umbra Partial Lunar Eclipse = Part of Moon in Umbra Penumbral Lunar Eclipse = Moon only in Penumbra
Time Lapse Partial Eclipses Time lapse shows moon moves thru Earth s shadow Curved shadow: Aristotle concludes Earth is sphere
Total Lunar Eclipse Moon moves its diameter in an hour Through the earth s umbra part of the shadow, ~2.5X moon s diameter =1.5 hours in totality
Red Moon in Totality White light from the sun scattered in Earth s atmosphere Blue scattered more so red gets through Color depends on clouds, volcanoes etc.
Lunar Eclipse as Seen from Moon
Solar Eclipse movie Fred Espenak s MrEclipse.com
Umbra=Total & Penumbra=Partial
Partial Solar Eclipse Most solar eclipses are partial and are not noticed Except by photographers Proper solar filters very important
Partial & Total Eclipses First the moon covers part of the sun = Partial phases When totality occurs it is about as dark as a night lit by a full moon The stars come out Lasts a few minutes Path of totality ~ hundred kilometers in diameter
Solar Corona Digital composite of 22 negatives 21Jun01 from Zambia Composite 01Aug07 eclipse, Russia Streamers and holes magnetic fields
Prominences Chromosphere is atmosphere of sun Prominences are Earth sized condensations in the Chromosphere
Moon at Apogee & Perigee Apogee= Far from Earth Perigee= Close to Earth
Annular Eclipse When Moon is at apogee and appears smaller than the sun Moon s shadow doesn t reach Earth
Eclipses Happen at Full &New Moons Solar eclipses happen only when the Moon is New Lunar Eclipses happen only when the Moon is Full
1 st Eclipse Season
2 nd Eclipse Season
Only at the Nodes of the Moon s Orbit Lunar orbit is tilted by 5 degrees So not all new/full moons are eclipses Eclipse season twice a year
Eclipse Seasons = solar eclipses; = lunar eclipses Eclipses happen when sun is at a node; ~twice a year
Precession of Moon s Orbit Line of nodes connects nodes = intersection of moon s orbit and Earth s orbit Moon s orbit precesses 360 in 18.6 years So Eclipse Season starts 19 days earlier each year
North American Total Solar Eclipses
Solar Eclipse 21Aug17
If there is a solar eclipse on 21Aug then: a. There could be a lunar eclipse on 28 Aug b. There could be a lunar eclipse on 07 Aug c. There could be a solar eclipse on 21 Oct d. The moon was passing thru the penumbra of the Earth s shadow e. The sun was at one node and the moon was at the other node
Columbus Predicts Lunar Eclipse 29 Feb 1504 Columbus was running out of food and the Jamaican natives would not trade for trinkets so He set up a meeting to coincide with the lunar eclipse
Saros Cycle Saros cycle (19 eclipse years=223 synodic months) = 18years 11days and 8hours After 3 Saros cycles= 54 yrs 1 month same eclipse occurs
The Big Moon Illusion Small Angle Formula Angular Diameter in arc seconds/206265 = Linear Diameter / Distance
Inner Corona & Diamond Ring Tenuous extremely hot outer atmosphere is called corona Occasionally sun shines through lunar valley forming Diamond Ring