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NUMBER
II-Bb TITLE: Field of View – Supplementary Exercise
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OBJECTIVE:
·
Calculate the
true Fields-of-View of several eyepiece-telescope combinations
·
By using TheS
DESCRIPTION:
Celestial objects
come in a variety of sizes and shapes.
When observing the moon, a planet, star cluster, or any celestial
object, the size of the field of view (True Field) of a telescope will
determine how much of the object will fit into the area of s
PROCEDURES AND OBSERVATIONS:
I. Magnification and FOV
1.
Calculate and
record in Table D: Do and Fo of;
a.
A 8 in f/6.3
telescope.
b.
A 10 in f/10
telescope.
2.
Calculate and
record in Table D: the magnification and
True FOV of
a.
A 8 in f/6.3
telescope with a 30 mm eyepiece
b.
A 10 in f/10
telescope with a 12 mm eyepiece?
TABLE D – TheS
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Telescope |
Eyepiece |
Do |
Fo |
M |
TFo |
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10 in f/10 |
12 mm |
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8 in f/6.3 |
30 mm |
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inner |
xxxx |
xxxx |
xxxx |
xxxx |
0.5 O |
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mid |
xxxx |
xxxx |
xxxx |
xxxx |
2.0 O |
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outer |
xxxx |
xxxx |
xxxx |
xxxx |
4.0O |
II. Locating
Objects in the Sky
- Set the time to
- Go to View Menu, Select Status Bar, Select Field
Width
- Go to View Menu, Select Field of View Indicators
- Select:
- Telrad
- 8 in
f/6.3 30 mm eyepiece
- 10 in
f/10 12 mm eyepiece
- Select the Pole
Up icon on the menu bar or go to Orientation
Menu, select Pole Up
- Find Betelgeuse – center on it
- Zoom in until FOV is between 8 – 9 degrees
- Using the up-down, left-right scroll bars and
your SC001 chart to “star-hop”, slew your “Telrad View” of the sky until
you locate M42 - attempt to center
it
- Select M42 – The Great Orion Nebula, (right click
on it) and center it (use the icon at the bottom left of the information
box)
- Zoom in and determine what Telescope/eyepiece
combination would give the best view of M42 (a view that shows most of the
nebula in the eyepiece? Record the
answers in your Bluebook
- What is the limitation when using the Telrad to
locate objects in the eyepiece by “Starhopping”?
Put the answer in your Bluebook
III. Large
Star Clusters FOV
1.
Find and center
M45
2.
Zoom in and
determine what telescope/eyepiece combination or Telrad ring would be best for
viewing the Pleiades
Put the answer in your Bluebook
IV. Separating
Double Stars
1.
Find and center
on Albireo
2.
What telescope/eyepiece
gives the best view of the two stars of the double star Albireo?
Put your answers in your Bluebook
V. Moons of
Jupiter
1.
Find and Center
Jupiter
2.
What eyepiece
gives the best view of Jupiter and all its moons?
Put your answer in your Bluebook
VI. STAR DRIFT METHOD Using TheSky
1. Go
the View Menu, Select Field of View
Indicators. Select:
a. the
Telrad,
b. 8
in f/6.3 telescope with 30 mm eyepiece and
c. 10
in f/10 telescope with 12 mm eyepiece and
d. click
OK
2. Select
the South (S) direction button on
the toollbar
3. Set
the Time Interval to 0.1 second
4. Use
your SC001 chart and select a star
near the Celestial Equator. Center Star in FOV with the time advance
stopped.
5. Zoom in/out
until the inner and middle Telrad FOV indicator rings, and the 8 in and 10 in
telescope FOV indicator rings are within the screen.
6. Use
the clock on the front wall of the lab to measure time intervals
7. Wait
until the time reaches :00 seconds. Note
the time in minutes and seconds, and immediately select the automatic time
advance double arrow.
8. When
the center of the star reaches each of
the following FOV rings the note the time to the second and record in Table
E:
a. 10
in telescope ring
b. Smallest
of the three Telrad rings
c. 8
in telescope ring
d. Middle
Telrad ring
9. Complete Table E
10. Which method of measuring FOV gave the best
agreement with the actual values – The Direct Method or the Star Drift method
Record your answer in your Bluebook
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TABLE E – Data for Star Drift Method |
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Telescope/ Eyepiece |
Half-Times
(sec) |
Times “T”
(sec) |
TFo
(EQ. #4) |
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10
in f/10 12
mm |
x2= |
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8
in f/6.3 30
mm |
X2= |
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middle |
X2= |
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X2= |
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TFo= T/240sec
This is a conversion from time to
angle based on the Earth’
EQ. #4