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Transcript ASTRONOMY notes

At the end of this unit you will be able to:
Calculate the number of degrees the sun moved, or the earth
rotated, in a given time
Calculate the eccentricity of an orbit
Label a diagram of the hemisphere and show the setting and
rising positions of the sun.
Locate Polaris
State what direction the earth rotates
Differentiate between Geocentric and Heliocentric models
State the difference between Jovian and Terrestrial Planets
Define: Orbit, ellipse, Penumbra, Umbra, Eclipse, Rotation,
Revolution, Constellation
Read The Luminosity chart in the reference tables
 How out of Round am I?
 Red
shift: indicates that celestial objects are
moving apart (distance is increasing,
 Galaxy:
collection of stars, gases and dust
held together by gravity
 Star:
large ball of gas that produces energy
and shines
 Luminosity:
how bright an object is
compared to our sun
 Asteroid:
solid, irregularly shaped object
that orbits the sun
 Comet:
an object with a very eccentric
orbit, vaporizes as it travels leaving a tail
behind it
 Meteor:
small solid fragment that burns up
in the earth’s atmosphere
 Terrestrial: rocky core, high density
 Jovian:
gaseous core, low density
 Rotation:
to spin on an axis
 Revolution:
to travel around an object
 Orbit:
path of an object revolving around
 Aphelion
(apogee): point in an orbit where
it is farthest from the sun, least gravity,
slowest orbiting speed
 Perihelion
(perigee): point in an orbit
where it is closest to the sun, greatest
gravity, fastest orbiting speed
 Ellipse:
shape of an orbit
 Foci
(focus): fixed object in space around
which an object orbits (revolves)
 Eccentricity:
how out of round an orbit is,
degree of flatness, value between zero and
 Gravitation:
(gravity) attractive force
between two objects
 Geocentric:
Earth at the center
 Heliocentric:
Sun at the center
 Constellation:
A group of stars that make a
 Tides:
rise and fall of the sea level caused
by the moons gravity
 Eclipse:
when a celestial object falls into the
shadow of another celestial object
 Penumbra:
 Umbra:
partial shadow
total shadow
A. Night Sky
1. Constellations: A
group of stars that
make a pattern in the
2. Polaris, aka north
star, located above the
North Pole and The
Earth’s axis of rotation
a. the ALtitude of Polaris equals your
4. Stars appear to move East to West in a
counterclockwise motion at the rate of 15
degrees per hour.
 Star
trails are made by leaving your camera
shutter open and pointed at the location that
marks the Earth’s Axis of rotation.
 If
the Camera is in the Northern Hemisphere
you would point it at what?
 If
you were in the southern Hemisphere
 would you have a star at the center of the trail?
1. The Sun rises in the east and sets in the
2. Moves across the Sky at the rate of 15
degrees per hour.
3. Sun looks like it moves because the
earth is rotating.
4. At the poles your travel slower than you
would at the equator.
5. Rotation of the earth evidence
a. Focult pendulum and Coriolis effect.
b. Sun rising and setting (once a day)
1. We have seasons because the earth is
a. the earth is tilted at an angle of 23
1/2 degrees from straight up.
 Seasons
2. Summer (Solstice)
a. June 21st
b. Longest day of sunlight
c. Highest altitude of sun in the sky
2. Summer (Solstice)
d. shortest shadow
e. longest arc or path of the sun
f. Rises NE and sets NW
3. Winter (Solstice)
a. December 21st
b. Shortest day of sunlight
c. lowest altitude of sun in the sky
3. Winter (Solstice)
d. longest shadow
e. shortest arc or path of the sun
f. Rises SE, sets SW
4. Fall and Spring (Equinox)
a. Equal amounts of daylight and
night time (12 and 12)
b. March 21st and September 21st.
4. Fall and Spring (Equinox)
c. Rises on East ands sets on West.
d. Sunlight rays are directly on the
 sun
path across sky looking at Polaris
Solar Eclipse: When the Sun
and moon and earth are
lined up. The moon is
between the earth and the
When the Sun and moon
and earth are lined up.
The earth is between the
moon and the sun
of “out of
roundness” of an ellipse
determined by the distance
between the two foci
divided by the length of the
major axis of the ellipse
value of eccentricity
is between ZERO (which is
a perfect circle) and ONE
(which is a line)
Spring tides
occur during the
full moon and the
new moon.
Neap tides occur
during quarter
68 (21-
24, 27)
Page 70 (2840)
A. Types
of models
1. Geocentric:
Earth is at the
center of the
solar system
2. Heliocentric
The Sun is at
the center of
the solar
1. Jovian planets: Gaseous
planet, low density, these
include: Saturn, Jupiter,
Neptune, and Uranus
These include; Mercury,
Venus, Earth, Mars
These planets have a rocky
core and are the closest to
the sun
 Please
complete on scrap paper
 Page 65 (15-19) and page 68 (20-27)
1. We classify stars based on
their luminosity, compared
to our sun.
2. P 15, ESRT
3. Stars moving towards us
are more of a blue or violet
4. Stars moving away are
Analogy: Bloody nose, fist has
already hit you and is moving
away from your face
5. The fact that the star
colors are changing are
indications that the universe
is either expanding or
We live in the Milky Way
Galaxy; it is called that
because it looks Milky
white in color
Earth in Persective
2. Lenticular
3. Elliptical
4. Irregular
a bubble sheet
Page 40 (1-6)
Page 44 (7-23)
Page 51 (30-50)