1. Today’s Comments
D2L Quiz 3 & 4 available (#4 has first few questions from next lecture)
Test 1 on Feb. 10.
Special tutor session with Gustavo: Thurs, Feb. 5, 3-5pm
Best test prep: 1. objectives, 2. D2L quizzes, 3. lectures/notes, 4. book
Sunset – Part 1 Due Feb. 12 (in 2 weeks)
Sunrise and Sunset times
Phone App: Sunrise Sunset
Moon Phases Due Mar. 2
Moon visible times: (Moonrise and Moonset)
Phone App: Phases of the Moon Free
Exploradome Planetarium Feb. 3 in T bldg plaza, 1st floor
9am to 12pm – come for a minute presentation, every half hour. Shows at 9, 9:30, 10, 10:30, 11 and 11:30am.
Check-in with me. Counts for lecture that DAY & lab for the WEEK

2. Prior to the Copernican Revolution – Greek Astronomy
Western only – Please investigate other cultures
Greeks (influenced by Babylonia, Mesopotamia, Egypt, Rome)
~700 BC to ~140 AD
Some ideas and people
Know the starred* items

3. Everything orbits around…
Earth
Sun
Heliocentric Model*
(from Copernicus, AD)
Geocentric Model*
(from Aristotle, BC)

4. Prior to the Copernican Revolution – Greek Astronomy
~700 BC Early astronomy was about time keeping (when to sow and reap crops)
Prior to the Copernican Revolution – Greek Astronomy

5. Prior to the Copernican Revolution – Greek Astronomy
Hesiad, Works and Days
... when the Pleiades rise it is time to use the sickle, but the plough when they are setting; 40 days they stay away from heaven; when Arcturus ascends from the sea and, rising in the evening, remain visible for the entire night, the grapes must be pruned;…
Needed better observations to keep the various calendars synchronized.
Prior to the Copernican Revolution – Greek Astronomy

6. Prior to the Copernican Revolution – Greek Astronomy
Greeks ~Fifth Century BC
What is the sun? Fire?
Tiny lights in the sky?
Why do 7 lights wander among the others? (7 Planetes*)
science.msfc.nasa.gov/ ssl/pad/solar/surface.htm
imagine.gsfc.nasa.gov/.../ news/22apr02.html
Prior to the Copernican Revolution – Greek Astronomy

7. Prior to the Copernican Revolution – Greek Astronomy
Pythagoras of Samos ~500 BC
Earth is a sphere
Sphere is perfection in math
Crystal spheres for 7 planetes Sun, Moon, 5 others
Already thinking geocentric
Prior to the Copernican Revolution – Greek Astronomy

8. Prior to the Copernican Revolution – Greek Astronomy
Plato ~360 BC
Heavens are perfect, unchanging (from mathematical perfection)
Heavenly motion must be in circles and uniform
Prior to the Copernican Revolution – Greek Astronomy

9. Prior to the Copernican Revolution – Greek Astronomy
Aristotle ~350 BC
Plato’s student
Earth: Corrupt, changeable, imperfect
(separation of heavens and Earth)
Arguments for geocentric model*
No parallax of stars*
and
Moon would be left behind*
Parallax is the apparent change in position of an object due to the change in position of the observer
Parallax thumb demonstration
Prior to the Copernican Revolution – Greek Astronomy

10. Prior to the Copernican Revolution – Greek Astronomy
Aristarcus ~300 BC
Heliocentric solar system (first evidence)*
Measured size of Sun
Measured that Sun was much further away than Moon
Prior to the Copernican Revolution – Greek Astronomy

11. Prior to the Copernican Revolution – Greek Astronomy
Ptolemy ~140 AD
Geocentric model* (often called the Ptolemaic system)
Mathematical model of universe*
Perfect Bodies and orbits
circles, spheres
Uniform motion
Epicycles* (retrograde motion)*
Prior to the Copernican Revolution – Greek Astronomy

12. From Moon Lectures Already know this: New information:
Minute to Minute: the Sun, Moon, stars, planets appear to rise in East and set in West due to Earth’s spin (rotation).
Day to Day: Moon moves West to East due to Moon’s orbit (revolution) around Earth.
New information:
Day to Day: Planets typically move West to East due to their orbits around the Sun.
Retrograde Day to Day Motion: Planets move East to West due to their orbits around the Sun and the difference in speeds of Earth and other planet.

13. Retrograde Motion (Day to Day)
Sometimes planets moved backwards against the background of stars.
All other planets have retrograde motion in our sky: inner planets and outer planets
Retrograde motion is East to West and observed day to day.
Minute to minute motion across sky is still East to West due to Earth’s rotation.

14. Perfect circles, spheres, uniform motion
Ptolemy
Geocentric Model
Perfect circles, spheres, uniform motion
Mars’ Epicycle
Earth
Mars

15. Copernican Revolution
Both models explain observations…
Retrograde motion of planets
Copernican Revolution

16. Copernican Revolution
Retrograde motion – Geocentric
Planets ride on epicycles
Sometimes appear
to move backwards
Copernican Revolution

17. Copernican Revolution
Retrograde motion – Heliocentric
One planet overtakes
another planet.
Slower planet appears to
move backwards.
Copernican Revolution

18. Copernican Revolution
Retrograde motion – Heliocentric
New (and correct) explanation of retrograde motion of the planets.
Retrograde (westward) motion of a planet occurs when the Earth passes the planet.
Ptolemy’s epicylces unnecessary
Copernican Revolution

19. Prior to the Copernican Revolution – Greek Astronomy
Dark Ages in Europe (5th to 15th centuries AD)
Roman libraries sacked
Often violent mix of Latin and Arabic cultures
Plague, famine, war
Islamic Golden Age of Science
Long time between Ptolemy ~140 AD to Copernicus ~1500 AD.
Prior to the Copernican Revolution – Greek Astronomy

20. Summary Before Copernicus ~700BC to 140 AD Geocentric Model Dominated
Pythagoras of Samos
Plato
Aristotle*
Aristarchus*
Ptolemy*

21. Observation Projects OBSERVING PROJECTS (in order of due date)
Each line below is worth 10 points for a total of 80 points.
Planetarium (Exploradome at MCTC): Feb. 3
Sunset – Part 1 Start: Jan. 20; Due: Feb. 12
Moon Phases Start: Jan. 22; Due: Mar. 3
Safe Sun Prep Work Start: Mar. 19; Due: Mar. 26+
Sunset – Part 2 Start: Apr. 2; Due: Apr. 28
Moon Craters Start: Jan. 29; Due: May 5
Star Gazing Start: Jan. 29; Due: May 5
Telescope Start: Jan. 29; Due: May 5

22. Observations Star Gazing Observation Telescope Observation
Main Goal: See constellations in night sky
Telescope Observation
Main Goal: Look at night sky through a telescope
Moon Craters Observation
Main Goal: see Moon’s craters under magnification
Jan. 29 to May 5 to complete
7 Options for each of these 3 observations
Class website has more details.
Turn in verification sheet (unless you check-in with me at the event).
3 on calendar starting today; 5 that you can be working on including sunset and moon phases

23. 6 Locations for Star Gazing, Telescopes & Moon Craters
Options
Eagle Lake Observatory at Baylor Regional Park (complete star gazing and telescopes together and possible moon craters) - every other Sat. until Nov.
Easiest way to complete but about an hour drive & $5/car
Jackson Middle School Observatory (dates TBD) – Champlin, MN
Eisenhower Community Center (dates TBD) – Hopkins, MN 7-10pm (call for reservations)
University of MN (Fridays TBD) – Minneapolis, MN
Macalester College (Thursdays TBD) – St. Paul, MN
St. Thomas College (weeknights TBD) – St. Paul, MN
Trying to get an option at MCTC for this but not sure if it will happen.

24. 7th Option (at home) for Star Gazing, Telescopes & Moon Craters
Star Gazing Observation
Star gaze with friends and write a short report
Telescope Observation
Use your/friends’ telescope and write a report (talk to me)
Moon Craters Observation
Use binoculars (from my office) and write short report

25. Star Gazing Observation
Main Goal: See constellations in night sky
Jan. 29 to May 5 to complete
7 Possible Options
Must have an expert point out constellations OR write a report
Eagle Lake Observatory at Baylor Regional Park (complete star gazing and telescopes together and possible moon craters) – every other Sat. until Nov.
Best view and experience but about an hour drive & $5/car
Jackson Middle School Observatory (date TBD) – Champlin, MN
Eisenhower Community Center (dates TBD) – Hopkins, MN 7-10pm (call for reservations)
University of MN (Fridays) – Minneapolis, MN
Macalester College (Mondays or Thursdays) – St. Paul, MN
St. Thomas College (weeknights TBD) – St. Paul, MN
Star gaze with friends and write a short report
Class website has more details.
Turn in verification sheet.

26. Telescope Observation
Main Goal: Look at night sky through a telescope
Jan. 29 to May 5 to complete
7 Possible Options
Eagle Lake Observatory at Baylor Regional Park (complete star gazing and telescopes together and possible moon craters) - every other Sat. until Nov.
Best view and experience but about an hour drive & $5/car
Jackson Middle School Observatory (dates TBD) – Champlin, MN
Eisenhower Community Center (dates TBD) – Hopkins, MN 7-10pm (call for reservations)
University of MN (Fridays TBD) – Minneapolis, MN
Macalester College (Thursdays TBD) – St. Paul, MN
St. Thomas College (weeknights TBD) – St. Paul, MN
Use your/friends’ telescope and write a report (talk to me)
Class website has more details.
Turn in verification sheet.

27. Moon Craters Observation
Main Goal: see Moon’s craters under magnification
Jan. 29 to May 5 to complete
7 Possible Options (Must have visible Moon, ideal is half Moon)
Eagle Lake Observatory at Baylor Regional Park (complete star gazing and telescopes together and possible moon craters) - every other Sat. until Nov.
Best view and experience but about an hour drive & $5/car
Jackson Middle School Observatory (dates TBD) – Champlin, MN
Eisenhower Community Center (dates TBD) – Hopkins, MN 7-10pm (call for reservations)
University of MN (Fridays TBD) – Minneapolis, MN
Macalester College (Thursdays TBD) – St. Paul, MN
St. Thomas College (weeknights TBD) – St. Paul, MN
Use binoculars (from my office) and write short report
Class website has more details.
Turn in verification sheet.