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NUMBER
III.C. TITLE:
The Moon
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DESCRIPTION:
The moon is our nearest celestial
neighbor and the easiest to observe with a small telescope. A variety of lunar features are easily seen
at different phases of the moon. The
craters, cracks, and mountains are most prominent during early waxing or late
waning phases when shadows emphasize the moon’s rugged contour. During mid gibbous and full phases, the maria (‘seas’) and rays are best
seen. This exercise will introduce an
observer to some of the better known lunar surface features to view through a
small telescope. It will also present
techniques for measuring photographs to determine the size of surface features.
OBJECTIVE:
·
Observe the moon with small telescope if weather permits.
·
Determine the ‘phase-age’ of the moon using a computer or
lunar calendar.
·
Identify a variety of lunar surface features.
·
Measure the height of a mountain on the moon and the
diameter of several craters.
·
Use the ‘Bluebook’ moon chart (p. F19) for identification of
moon features.
TELESCOPE
OBSERVATIONS:
Set up the Meade Telescope using
the 40mm eyepiece and higher power eyepieces to observe greater detail.
1. Sketch and describe the location of
five different surface features. Use the
map in your Bluebook to verify their identity.
Also check off the feature in the log section.
Indicate
Eyepiece and Magnification in each sketch box.
1. 2. 3. 4. 5.
2.
Try different filters and decide which enhances the
viewing of the moon the most.
This may differ for various phases of
the moon.
NOTE – Viewing the full or near full moon with a Meade may hurt your eyes. Use filtration or reduce telescope aperture.
Comment on observations below:
PHOTOGRAPHIC
MEASUREMENTS: (Indoors)
Measure
the radius of the photo on the next page in millimeters. Determine the ‘PLATE SCALE’ of the lunar
image (km/mm).
PHYSICAL
RADIUS OF THE MOON = 1738 km.
mm
MEASURED
RADIUS OF THE MOON PHOTO =
PLATE
SCALE = PHYSICAL RADIUS OF MOON/MEASURED RADIUS OF PHOTO.
km/mm
This
is a very important number. Make careful
measurements since the accuracy of the rest of
the exercise will depend upon it.
1. Using your
Bluebook moon map, identify craters ‘B’ and ‘C’ on the adjacent photo.
B = C
=
Measure the image diameter of both
craters and then determine the physical or actual diameters (in km) of
each. Calculate the % discrepancy after
instructor gives the published values for each.
Show calculations and results below:
2. Determine the
height of the mountain peak, Piton. This
can be done by using the formula below, where H is the height of the mountain, L is the length of the shadow cast by the mountain, D is the distance of the mountain peak
to the terminator, and R is the radius of the moon photo (as
marked).
H
= L x D x (Plate Scale)
R
Show all measurements and calculations below, including
discrepancy. Instructor will give
published altitude of Piton.
QUESTIONS:
1.
What crater is the ray marked ‘A’ in the photo associated
with?
2.
What is the phase age of the moon when the moon photo was
taken?
3.
What is the phase and phase age of the moon on April 15 of this year?
4.
Give several reasons for discrepancies in measurements off
photo.
a. crater diameter b. mountain height
