Transcript The Changing Sky upgraded April 2011

The Changing Sky
Analyzing Images of the Sky
As Time Goes By
with Rick Kang
Public Education/Outreach Coordinator
Pine Mt. Electronic Universe
“Cradle-Cam” CCD was used by
students to acquire sky data.
• A CCD (Charge Coupled Device) is
the small grid of silicon that
actually creates the picture
(image) in a DIGITAL CAMERA.
• CCDs convert the energy of the
incoming light (PHOTONS) into
ELECTRICAL CHARGE
(ELECTRONS)
OMSI Space Camp 9th-10th grade
students set up camera outside
at PMO, Aug 06. Wide Field.
For each direction (S, W, N, E) we took two
images 5 minutes apart, and also took
a 30 second “time exposure” to record trails.
Looking to South Horizon
Add LITTLE ARROWS to South
Stars to show your prediction
of their location 5 mins later.
• Please ONLY consider the few stars above
Southern Horizon, we’ll work on others
one section at a time.
• Should all your arrows for stars above one
horizon point the same direction, or in
various directions? Consider the idea of a
Constellation.
South horizon comparison
30 second South Trails,
correct arrows on your diagram.
Looking to Western Horizon
Add LITTLE ARROWS to West
Stars to show your prediction of
their location 5 mins later..
Western horizon comparison
30 second West Trails,
correct arrows on your diagram.
Not meteor trails, why not?
Looking to Northern Horizon
ALERT!
DO NOT MARK ANY ARROWS
ON POLARIS NOR ITS FOUR
SURROUNDING STARS YET!
Add LITTLE ARROWS to North
Stars to show your prediction
of their location 5 mins later.
Northern horizon comparison
see the meteor?
30 second North Trails,
correct arrows on your diagram.
Looking to Eastern Horizon
Add LITTLE ARROWS to East
Stars to show your predictions
of their location 5 mins later.
Eastern horizon comparison
30 second East Trails,
correct arrows on your diagram.
With all FOUR HORIZON
APPARENT MOTION DIAGRAMS
DONE,
DO YOU SEE AN OVERALL
PATTERN?
Now let’s consider POLARIS and
its surrounding stars:
Add tiny arrows to indicate
which of these stars will appear
to move if we wait for 10
minutes.
Polaris *
10 minute Polaris Trails,
correct arrows on your diagram.
• Does Polaris need an arrow?
• Is your motion consistent with your
other four pieces of data?
INQUIRY QUESTIONS
• Why do the stars APPEAR to circle the
sky around Polaris?
• Why does Polaris appear as the central
star, and why doesn’t Polaris appear to
move?
Write a “CLAIM” about your
observations and analysis.
• Example:
Stars appear to circle around Polaris
BECAUSE
stars follow curved tracks within the
spiral arms of our Galaxy.
Can you think of several
explanations that would prove
your claim true or prove your
claim false?
Can you come up with ideas or
experiments/observations to
validate or to dismiss any of the
claims made by you or your
associates?
What do you think is the most
likely simple explanation for
what you’ve just observed
happen to the sky over several
minutes of time?
Now let’s consider how the sky
might APPEAR to change over
LONGER periods of time:
Remember the first South
Horizon View?
If you return 24 hours later,
sketch apparent motions of key
stars relative to tree/horizon
Comparison South Horizon
Night 1 to Night 2 –
draw arrows on your diagram.
How about night 3? Sketch your
prediction.
Comparison of Night 2 to Night 3
SAME CLOCK TIME
Sketch your prediction for
Northern Sky night 1 and night 2
Here’s the Northern Sky
comparisons, SAME CLOCK
TIME, 24 hours apart –
Sketch arrows on your diagram.
What’s your “CLAIM” for the
sky motion that you’ve just
seen?
Can you come up with some
evidence/explanations and
arguments for true or false?
What might be the most
reasonable explanation?
Be careful of the terminology
that you use.
How many times have you
personally been around the
Sun?
• What’s the evidence for your travels?
• How often do you make the trip?
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