Download Celestial Sphere

RECAP
Refractor and Reflector
Lens
Mirror
The Celestial Sphere
&
more on
Constellations
(Week 4)
Why do we see what we see??
90 deg.
34 deg.
Latitude
Rotation
Daily Changes
Revolution
Monthly Changes
The Zodiac
Constellations – the 88 semirectangular regions that make up the sky
• Northern constellations have Latinized
Greek-mythology names:
– Orion, Cygnus, Leo, Ursa Major, Canis Major,
Canis Minor
• Southern constellations have Latin
names:
– Telescopium, Sextans, Pyxis
What do you think?
• What causes the stars to move?
• Do the stars actually move in the way they
appear from Earth?
• Do the stars stay in the same position in the
sky all day/night long?
Consider the dome of the sky over our heads….
mixing bowl
Consider the dome of the sky over our heads….
inverted mixing bowl ….
Imagining a spinning
Celestial Sphere
surrounding Earth
aids in thinking
about the position
and motion of the
sky
Animation of Celestial Sphere
http://bcs.whfreeman.com/universe6e/pages/bcsmain.asp?v=category&s=00110&n=01000&i=02110.02&o
=|02000|01000|&ns=0
Imagining a spinning Celestial
Sphere surrounding Earth aids in
thinking about the position and
motion of the sky
Altitude is like
latitude or
declination
Celestial Sphere Rotation
Celestial Sphere Rotation
Star B
Star B
2
2
Star A
Star A
1
2
1
2
North Star
Celestial Sphere
Celestial Sphere
3
3
1
1
4
4
3
3
Horizon
Earth’s Equator
4
4
Celestial Sphere
Rotation
Celestial Sphere
Rotation
Figure 1
Figure 2
1) Explain how to find North on the horizon from the North star.
2) Where is the North star when you’re at the North pole?
1) Is the horizon shown a real
physical horizon, or an
imaginary plane that extends
from the observer and Earth
out to the stars?
Celestial Sphere Rotation
Star B
2
Star A
1
2
Celestial Sphere
2) Can the observer shown
see an object located below
the horizon?
Celestial Sphere
3
1
4
3
3) Is there a star that is in an
unobservable position?
4)When a star travels from
being below the observer’s
horizon to being above the
observer’s horizon, is that star
rising or setting?
4
Celestial Sphere
Rotation
Figure 2
Horizon
•
•
•
•
•
•
Tutorial: Position – p.1
PUT
NAMES
in
Tutorials
Work with a partner
Read the instructions and questions carefully
Talk to each other and discuss your answers with each another
Come to a consensus answer you both agree on
If you get stuck or are not sure of your answer ask another group
If you get really stuck or don’t understand what the Lecture Tutorial is asking ask
your Professor for help
• I WILL BEGIN STAMPING TUTORIALS A LITTLE
BEFORE YOU FINISH THE TUTORIAL SINCE THERE ARE
70+ OF YOU, BUT YOU MUST ALL FINISH THE
TUTORIAL OR YOU WILL GET A ZERO! DO NOT WALK
OUT OF THE ROOM OR GET OFF TASK WHEN WE ARE
COMPLETING A TUTORIAL OR YOU WILL GET POINTS
DEDUCTED OR GET A ZERO!
• IF THE TUTORIAL IS COMPLETED AT THE END OF
LECTURE, NO ONE IS ALLOWED TO LEAVE EARLY
UNLESS YOU CHECK WITH ME FIRST! IF YOU LEAVE
EARLY YOU’LL GET A ZERO.
Did you get the Key Ideas from the Position
Lecture Tutorial?
Celestial Sphere Rotation
Star B
In what
direction is the
observer
facing?
2
Star A
1
2
Celestial Sphere
Celestial Sphere
3
1
4
3
4
A.
B.
C.
D.
toward the South
toward the North
toward the East
toward the West
Celestial Sphere
Rotation
Figure 2
Horizon
Imagine that from your current location you
observe a star rising directly in the east.
When this star reaches its highest position
above the horizon, where will it be?
Celestial Sphere Rotation
A.
B.
C.
D.
high in the northern sky
high in the southern sky
high in the western sky
directly overhead
Star B
2
Star A
1
2
Celestial Sphere
Celestial
3
1
4
3
4
Celestial Sphere
Rotation
Figure 2
Horizon
Celestial Sphere Rotation
Where would
the observer
look to see the
star indicated by
the arrow?
A.
B.
C.
D.
High in the Northeast
High in the Southeast
High in the Northwest
High in the Southwest
Star B
2
Star A
1
2
Celestial Sphere
Celestial Sphere
3
1
4
3
4
Celestial Sphere
Rotation
Figure 2
Horizon
Telescope Field of View
Moon=0.5 deg.
Field of View = Eyepiece apparent FOV ÷ Magnification
Large Magnification = Small field of view
Small Magnification = Large Field of view
Right Ascension (RA) and
Declination (Dec) are similar
to latitude and longitude on
the surface of the Earth.
Latitude and longitude are
fixed with respect to positions
on Earth. But RA and Dec are
fixed with respect to positions
of stars in the sky.
What is moving, the celestial
sphere or the Earth?
To an Earthling observer,
what appears to move?
Declination (like latitude) is measured in degrees north or south of the Celestial
equator.
Right ascension (like longitude) is measured in units of hours, minutes, and seconds
eastward from the position of the vernal equinox on the Celestial equator. The Vernal
Equinox is the position of the Sun on the first day of Spring.