1. Charting the Heavens

3. Warm-up 9/15
Which constellation has the brightest star in the sky?

4. Galaxy and the Universe
The universe is the totality of all space, time and matter
The universe is constantly growing
Our galaxy is the milky way, and it spans 100,000 light years

5. Celestial Sphere
Formed from the apparent rotation of stars based on the earths spin
Consists of the North Celestial Pole, celestial equator, and south celestial pole
While technically incorrect, it gives us a way to better map the stars
Use “angular positions” to find locations of the stars

6. Motion of Sun and Stars
The basic social time unit is called a Solar Day, a 24 hour period
The passage of the sun, as well as other objects is called Diurnal motion

7. Sidereal day This is a day based on the rotations of the stars
This is different from a solar day because it is based not only on the earth’s rotation around the sun, but on the earth revolving around its own axis
The solar day is 3.9 minutes longer than the sidereal day

8. Seasonal Changes
The earth is tilted at about 23.5 degrees, which allows for what we know as seasons
At certain times of the year, certain parts of the earth get more/less sunlight, which changes the length of days and the average temperatures in the area

9. Seasonal Changes

10. Warm-Up 9/16
What is the difference between a sidereal and solar day?

11. Solstices These occur on the day when the earth is tilted the most
When the one side of the earth experiences cold weather, the other side of the earth experiences hot weather
Summer solstice: June 21st, longest day of the year for the Northern hemisphere
Winter Solstice: December 21; shortest day of the year for the Northern Hemisphere

12. Equinox
When the earth intersects the celestial equator we have an equinox
There are fall and vernal(spring) equinox

14. The Moon Completes phases in about 29 days
Consists of “waxing” and “waning phases”

15. Moon Phases Waxing phases consist of the moon getting brighter
Waning phases consist of the moon getting darker
These go together with gibbous and crescent phases

16. Moon Months 2 types of months:
Sidereal month: The time it takes for the moon to complete one revolution around the earth (27.3 days)
Synodic Month: The time it takes for the moon to complete it’s phases (29.5 days)

17. Lunar Eclipse
A lunar eclipse occurs when the earth blocks all sunlight to the moon
You can have 2 types of Lunar Eclipses; Partial and Total
Partial is an imperfect alignment between the sun, earth and moon but still occurs
Total is a perfect alignment
Can be seen by the whole entire night side of earth

18. Solar Eclipse When the moon blocks out the sun
Again, there are partial and total eclipses
Can only be seen by a small portion of the earth, unlike a lunar eclipse

19. Warm-up 9/21
What is the difference between an equinox and a solstice?

20. Triangulation
Using Trigonometry to find the location of certain objects

21. Parallax
a displacement or difference in the apparent position of an object viewed along two different lines of sight

22. Kepler’s first law
All planetary orbits are ellipses

23. Kepler’s second law
a line between the sun and the planet sweeps equal areas in equal times

24. Kepler’s third law
The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
Py2 = aAU3

26. Warm-Up 9/22 What is so important about today?!
(hint: it has to do with the earth’s tilt)