Transcript PH1600: Introductory Astronomy

PH1600: Introductory Astronomy
Lecture 4
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PH1600: Introductory Astronomy
Lecture 4: Moon Phases and Eclipses
Next time: Magnitudes and Calendars
School: Michigan Technological University
Professor: Robert Nemiroff
Online Course WebCT pages:
http://courses.mtu.edu/
This class can be taken online ONLY, class
attendance is not required!
You are responsible for…
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Lecture material
Listed wikipedia entries
 But not higher math
APODs posted during the semester
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APOD review every week during lecture
Completing the Homework-Quizzes
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Homework 1 quiz already due
Homework 2 quiz is due soon
See WebCT at http://courses.mtu.edu/
Phases of the Moon
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Moon orbits Earth
Half of the Moon always illuminated
by the Sun
Only part of the lit-up half is usually
visible
Moon always points the same half
toward the Earth
“Dark Side of the Moon” sometimes
misunderstood
Wikipedia entries this lecture:
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Lunar phase
Diurnal motion
Celestial pole
Solar Eclipse
Lunar Eclipse
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http://en.wikipedia.org/wiki/Lunar_phases
Lunation
Credit & Copyright: Antonio Cidadio
APOD: 2007 September 2
Sun Rise versus Moon Rise
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Sun always rises in the East, sets in
the West
Moon always rises in the East, sets
in the West
Earth rotates “faster” than Moon
orbits
Lunar Phase Logic Puzzles
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Earth’s spin + lunar phase = logic
puzzles
How to solve: VISUALIZE
Example:
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Q: You are in Houghton, Michigan at 3
pm during a full Moon. When and
where is the nearest time you can see
this full Moon?
A: At sunset look east.
Eclipses
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Two types:
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Strange Coincidence:
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Solar Eclipse (Sun becomes dark)
Lunar Eclipse (Moon becomes dark)
Moon and Sun have nearly exactly the same
angular size
Angular size:
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The angle something takes up
 Nearby small things can appear angularly
large
 Far away big things can appear angularly
small
Total Solar Eclipse
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Moon totally blocks Sun
Visible only in small swath on Earth
Observer in Moon’s Umbra
Relatively rare
Solar corona becomes visible
http://en.wikipedia.org/wiki/Solar_eclipse
Eclipse in the Mist
Credit & Copyright: Olivier Meeckers (Groupe Astronomie de Spa)
APOD: 2003 June 4
A Total Solar Eclipse over Turkey
Credit & Copyright: Stefan Seip
APOD: 2006 April 4
Vanishing Umbra
Credit & Copyright: Stephan Heinsius
APOD: 2006 April 8
Looking Back on an Eclipsed Earth
Credit: Mir 27 Crew; Copyright: CNES
APOD: 2007 June 10
The Long Shadow of the Moon
Credit: Image courtesy J. Descloitres, MODIS Rapid Response Team,
GSFC, NASA
APOD: 2003 November 27
The Big Corona
APOD: 2001 April 8
Solar Eclipse in View
Credit & Copyright: Fred Bruenjes (moonglow.net)
APOD: 2005 April 7
When Diamonds Aren't Forever
Credit & Copyright: Anthony Ayiomamitis
APOD: 2006 March 30
Baily's Beads near Solar Eclipse Totality
Credit & Copyright: Leonid Durman
APOD: 2008 August 18
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Partial Solar Eclipse
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Moon partially blocks Sun
Visible only in small swath on Earth
Observer in Moon’s Penumbra
Relatively rare
Solar corona does NOT become
visible
Annular Solar Eclipse: Ring of Fire
http://en.wikipedia.org/wiki/Solar_eclipse
Annular Eclipse: The Ring of Fire
Credit & Copyright: Dennis Mammana (Skyscapes)
APOD: 2002 June 10
A Rare Annular Venusian Solar Eclipse
Credit & Copyright: Peter Lawrence
APOD: 2004 June 15
A Picturesque Venus Transit
Credit & Copyright: David Cortner
APOD: 2004 June 23
Mercury's Transit: An Unusual Spot on the Sun
Credit & Copyright: David Cortner
APOD: 2006 November 14
The Eclipse Tree
Credit & Copyright: E. Israel
APOD: 2000 December 25
Total Lunar Eclipse
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Moon becomes dark
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Slightly glows due to reflected Earthlight
Moon enters Earth’s shadow (both
Umbra & Penumbra)
Visible from anywhere on Earth
where the Moon is visible
Occurs during a full Moon
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Not every full Moon
http://en.wikipedia.org/wiki/Lunar_eclipse
November's Lunar Eclipse
Animation Credit & Copyright: Larry Koehn
APOD: 2003 November 7
Tonight: A Total Lunar Eclipse
Credit and Copyright: Vic Winter, ICSTARS
APOD: 1996 September 26
Kalamalka Lake Eclipse
APOD: 2007 September 1
Earth’s Shadow
Credit & Copyright: Anthony Ayiomamitis (TWAN)
APOD: 2008 August 20
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Twelve Lunar Eclipses
Credit & Copyright: Tunç Tezel (TWAN)
APOD: 2008 February 29
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Partial Lunar Eclipse
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Moon becomes partly dark
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Slightly glows due to reflected Earthlight
Moon enters Earth’s shadow (only
the penumbra)
Visible from anywhere on Earth
where the Moon is visible
Occurs during a full Moon
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Not every full Moon
Shadow Play
Credit & Copyright: Laurent Laveder (PhotoAstronomique.net)
APOD: 2006 September 9
From: http://www.mreclipse.com/
Future Eclipses:
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Lunar eclipses:
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2009 Dec 31 (partial)
2010 Jun 26 (partial)
2010 Dec 21 (full)
Solar eclipses
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2009
2009
2010
2010
Jan 26 (annular)
July 22 (total)
Jan 15 (annular)
Jul 11 (total)
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