AST 3722C  Spring 2008
Midterm. Due March 4th 2008 before class.
Instructions: Solve each problem below. Where math is involved, and unless otherwise
indicated, show your work. You can consult the book, your notes, and old homeworks, but
not other people. Each of the 33 problems has equal weight in scoring.
•
Part A.
Download and view the movie at this URL:
http
:
//
www
.
theastronomer
.
org
/
asteroids
/
2008
/
2007tu24
20080202
ndj
.
wmv
.
(If you have problems, see me.) An amateur astronomer took a sequence of digital pictures
of the same piece of sky and strung them together to make this movie. The moving object is
the asteroid 2007 TU
24
. The stationary dots are background stars, and you can see a couple
of galaxies too. The UTC of each frame is given at the top, as is the orientation of the
frame (northup, eastleft) and its ﬁeldofview (“FOV”). The frame is centered on J2000
coordinates
α
= 12
h
00
m
37
.
5
s
,
δ
= +33
◦
21
0
15
00
.
◦
1. The asteroid enters the ﬁeld of view at about UTC 00:56 and leaves at about UTC
02:53. Assuming these are the exact times, what is the asteroid’s average rate of motion in
Declination? Express your answer in arcseconds per hour.
◦
2. The asteroid’s motion in R.A. is 75 arcsec per hour. How many arcsec in R.A. does
it move while it is in the FOV?
◦
3. When the asteroid enters the FOV, its coordinates are
α
= 12
h
00
m
30
.
7
s
,
δ
=
+33
◦
27
0
31
00
(J2000). What are the coordinates of the asteroid when it leaves the FOV?
◦
4. The movie’s creator used a telescope in Chelmsford, northeast of London, England.
The latitude there is
φ
= 51
◦
33
0
. When the asteroid entered the FOV, the LST there was
09
h
44
m
25
s
.
What was the LST when the asteroid left the FOV?
◦
5. What was the altitude
a
of the asteroid when it entered the FOV? What was sec
z
,
the secant of the zenith distance?
◦
6. Suppose this asteroid had kept its motion in Declination for the foreseeable future.
(This is not actually true but suppose it is.) About how long would it be before the asteroid
would not be visible from Chelmsford anymore (i.e. would not ever rise above the horizon)?
Express your answer in integer days, no need to be more accurate than that.
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 Spring '09
 Fernandez
 Astronomy, Hubble Space Telescope, Telescope, Ecliptic

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