Transcript More About Individual Term Projects

More About Individual Term
Projects
Next Tuesday
• Meet at Abrams
Planetarium at the
usual time
Aurora
A few words on Huygens
Titan – Saturn’s largest moon
First Detailed images of the surface
From 16.2 km up
From 8km up
Mosaic of descent images
*Deadline*
• By next Tuesday, I would like you each to
turn in a one page description of your
individual semester project
Sample Projects
• Moon position
• Photographing planet motions
• Observing a variable star
Moon Position Project
• What you need:
– A chart of the night sky showing the
constellations visible at the time you are
observing (Abrams sky calendar charts are
good, but you may need more than the
January chart)
Mark location of the moon with
respect to the stars
In a notebook record:
• The date and time of
each observation
• The phase of the
moon (make a
sketch)
• Do not let your
observation be
influenced by
planetarium software
or other predictions
Goal
•
•
Do this on perhaps 10-15 nights during
the semester
Use your observations to determine
(a) The sidereal period of the moon
(b) The synodic period of the moon
(c) Estimate the uncertainty of each period
And compare these with the “book” values
Periods
• Sidereal period: The “true” orbital period of
the Moon. How long it takes the moon to
return to the same location with respect to
the stars
• Synodic period: How long it takes to return
to the same phase; based upon the
position of the Sun and Moon with respect
to the earth
Planet Motion Project
• For this project, you will need a camera
(most easily a digital camera) that can
take time exposures of a few seconds
duration
• For this project, it is OK to work as a team
of two people
Step 1: Image the planet and the
background stars (5 or 6 times in the
semester)
• Saturn and/or Jupiter are most easily done this
semester
Step 2
• Measure the position of the planet on the
image with respect to several stars
• Use the known right ascension and
declination of the stars to determine the
right ascension and declination of the
planet on each date
• Estimate the uncertainty of your measured
positions
Step 3
• Plot the changing
position of the planet
and compare your
results with the
predicted motion of
the planet
Variable Star Project
• Two possible targets
– Delta Cephei
– Algol (easier for naked
eye observations from
campus)
Delta Cephei Project
• Check out the “observing delta Cephei” tutorial at the AAVSO
website:
http://hoa.aavso.org/observing.html
Following the steps outlined there,estimate the brightness of
Delta Cephei on 12 or more nights during the semester
Calculate the “Julian Date” of each of your observations using the
website
http://wwwmacho.mcmaster.ca/JAVA/JD.html
Make a light curve
• Estimate the pulsation period of Delta
Cephei from your observations
• Calculate the “phase” of each of your
measurements:
Phase = Julian Date/period (Keep only the part
after the decimal point, i.e., if the phase
comes out to be 5.43 keep just the 0.43)
Plot a light curve
• Plot the observed
magnitude versus
phase (your plot may
not look this nice)
Algol
• Brighter than Delta Cephei and higher
overhead in the evening (easier to observe
without binoculars)
• Use your chart of Algol (you can download
another from the AAVSO website if
needed) to estimate the brightness of the
star, recording date and time
• Measure the brightness of Algol on at least 10 nights
• On at least one night when Algol is predicted to undergo
an eclipse, measure its brightness several times over the
span of 3 or 4 hours around the time of minimum
– Predicted times of minimum can be obtained
at the website
– http://skyandtelescope.com/observing/objects/variablestars/article_108_1.asp
Plot the light curve, as in the case
of Delta Cephei
•
In this case, you may use the known period of 2.8673 days if your observations do not
let you determine the period independently. You will need to observe more than one
minimum if you want to independently determine the period of Algol.
Other independent projects
• You may devise an
independent project
of your own, but you
will have to check it
out with me before
you do it