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ASSIGNMENT 9
Textbook Assignment: "Dead Reckoning, Piloting, and Electronic Navigation (continued),"
and "Celestial Observations and Sight Reduction Methods," chapters
8 and 9, pages 8-24 through 9-4.
9-1.
What is the principal function of a
sextant in navigation?
1.
To measure ranges to other
ships
2.
To measure the angle between a
heavenly body and the visible
horizon
3.
To determine the courses of the
ships
4.
To determine the true bearings
of navigational aids
Figure 9-A
9-8.
IN ANSWERING QUESTIONS 9-2 THROUGH 9-7
REFER TO FIGURE 9-A, THE MARINE SEXTANT.
9-2.
The index arm pivots about the
exact center of the curvature of
the part of the sextant marked with
what letter?
1. B
2. E
3. F
4. G
9-3.
What part pivots at one end to
allow the index mirror to reflect
on the horizon glass?
1. A
2. D
3. E
4. G
9-4.
9-5.
9-6.
9-7.
9-9.
9-10.
What part of the sextant is
parallel to the horizon glass when
the index mark is at zero and there
is no index correction?
1. B
2. C
3.
D
4.
F
What part of the sextant is the
horizon glass?
1. A
2. B
3. C
4. E
What part directs the observer's
line of sight?
1. B
2. C
3. D
4. E
What part protects the observer's
eye when viewing the Sun?
1. D
2. E
3. F
4. G
The micrometer drum of the sextant
is graduated in which of the
following increments?
1.
Half seconds from 0 to 180
2. Half seconds from 0 to 20
3.
Seconds from 0 to 60
4.
Minutes from 0 to 60
How many degrees is the sextant
index arm moved by one complete
rotation of the micrometer drum?
1.
10
2.
20
3.
50
4. 100
When you take a celestial
observation with the sextant, from
what part should the angular
reading be taken?
1.
Arc scale
2.
Micrometer drum
3.
Vernier scale
4.
Each of the above
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