Credit/Permission: For text, © David Jeffery. For figures etc., as specified with the figure etc. / Only for reading and use by the instructors and students of the UNLV astronomy laboratory course.
Sub Tasks:
The closest point of approach of an orbiting body to the
center of force is
generically called periapsis.
Special case names exist for particular
centers of force: e.g.,
perigee
for the Earth,
perihelion
for the Sun,
periastron
for a star,
etc.
For Jupiter as the
center of force, the special
case name is _____________ . HINT: What is the alternate
name for the Roman god Jupiter.
Sub Tasks:
Kepler's 3rd law
for a fixed center of force
(e.g., Jupiter for the
moons of Jupiter
to high accuracy/precision)
can always be written p**2 ∝ r**3, where
p is orbital period
and r is mean orbital radius.
For the moons of Jupiter,
we can rewrite the law as p_d = C * r_j**(3/2), where
p_d is orbital period
in days,
r_j is mean orbital radius
in equatorial Jupiter
radii,
and C is a constant.
Sub Tasks:
By following with your eye 2 adjacent-orbit
Galilean moons in the
animation verify
that the animation does
display the
1:2:4 Laplace resonance.
Did you verify it? _________ .
Omit this task if NO
conical pendulum
is available.
The formulae given in the figure above
(local link /
general link: pendulum_conical.html)
predicts that the period of
conical pendulum
with r ≅ 0.25 m and θ ≅ 45° will be P ≅ 1 s.
Swing the conical pendulum
with r ≅ 0.25 m and θ ≅ 45° and time it for for 10 periods.
Divide the swinging time by 10. Is the experimental
result consistent with the predicted 1 s to within 25 %?
Estimate and
then (if you have a protractor)
measure the astronomical phase angle
illustrated in the figure below
(local link /
general link: phase_angle_astro_jargon.html).
Each group should follow the instructions given with the figure below
(local link /
general link: galilean_moons_orbits.html)
and append the
completed diagram to favorite group member's report.
Sub Tasks:
Launch
TheSky.
Prepare and print a diagram of the
Solar System
for today.
Remember
TheSky date has to be set each time
(at least for the
TheSky6).
The diagram should be looking straight down from the
north ecliptic pole.
It should show only out to the orbit
of Jupiter.
Draw a triangle
with vertices
at the Sun,
the Earth,
and Jupiter.
You may need to consult List of Tricks for TheSky
to carry out the operations.
Measure the elongation
and astronomical phase angle
for Jupiter.
Do the values agree with those determined in
Task: Galilean Moon Orbits to within a few degrees.
____________ . If NOT, you've done something wrong.
Append the diagram to the favorite group member's report.
Sub Tasks:
Sub Tasks:
Sub Tasks:
Galileo's observations
of the Galilean moons
showed their sinusoidal motion
on the sky.
Sub Tasks:
Each PERSON in the group should draw their own
sky map
of the FOV
(using our standard 40 mm eyepieces) centered on
Jupiter.
Use the FOV figure below
(local link /
general link: field_of_view_blank.html)
for your sky map
and draw approximately to-scale.
Given the FOV
data given in
Table: C8 Telescope Magnification and Field of View
above
(local link /
general link: telescope_c8_mag_fov_table.html),
estimate the angular diameter of
Jupiter and put that value
on your sky map in brackets
near Jupiter's label.
To help identify which
Wikipedia: Galilean moon is which
and transits,
occultations,
eclipses,
and shadow transits
use Javascript Jupiter when you get back inside.
Figuring out the
NSEW is a a bit of trick.
You can find them on the
sky pretty easy since
the great circle path
through Jupiter
to the
north celestial pole (NCP)
(almost exactly at Polaris) is easy to find.
Then remember that the
telescope
point inverts the
FOV
and the star diagonal
mirror inverts
the FOV through the line
perpendicular its symmetry plane.
Repeat Task 16: Your Own Sky Map Centered on Jupiter
using a 9-mm eyepiece.
Sub Tasks:
EOF
EOF
_________________________________________________________________________
Table: Transit Times for the Galilean Moons
_________________________________________________________________________
Galilean Orbital Orbital Δθ ω Δt Δt_h
Moon Period p Radius r ≅d/r =2π/p =Δθ/ω =Δt*24
(days) (mm) (radians) (rads/day) (days) (hours)
Io 1.7691
Europa 3.5512
Ganymede 7.1546
Callisto 16.689
_________________________________________________________________________
As mean orbital radius
increases,
angular velocity ω
decreases which tends to increase
transit time,
but transit orbital arc length θ
decreases which tends to decrease
transit time.
Which trend wins out?
Include all the details you can see and label them if possible: i.e.,
Jupiter,
Jovian band structure,
Great Red Spot,
all Galilean moons,
transits,
shadow transit,
stars,
the astronomical NSEW approximately.
End of Task