Title: The Celestial Sphere
1The Celestial Sphere
2The Celestial Sphere
- Appears as a dome over our heads.
3The Celestial Sphere
- Appears as a dome over our heads.
- Stars seem embedded like tiny jewels
4The Celestial Sphere
- Appears as a dome over our heads.
- Stars seem embedded like tiny jewels
- Stars all appear to be the same distance from
Earth. - Makes a great model of what we see.
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6Model of the Celestial Sphere
7Notice that the Celestial Poles are directly
above the Earths Poles...
8C.N.P.
Notice that the Celestial Poles are directly
above the Earths Poles...
9C.N.P.
Notice that the Celestial Poles are directly
above the Earths Poles...
10C.N.P.
Notice that the Celestial Poles are directly
above the Earths Poles...
C.S.P.
11C.N.P.
Notice that the Celestial Poles are directly
above the Earths Poles...
C.S.P.
12C.N.P.
C.S.P.
13and that the Celestial Equator is directly above
the Earths Equator.
14and that the Celestial Equator is directly above
the Earths Equator.
Celestial Equator
15and that the Celestial Equator is directly above
the Earths Equator.
Celestial Equator
Celestial Equator
16Declination
17Declination is like latitude.
18Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
19Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
20Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
21Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
22Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
23Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
24Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
25Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
26Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
27Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
28 90o (dec)
Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
29 90o (dec)
Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
30 90o (dec)
Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
31 90o (dec)
Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
32 90o (dec)
Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
33 90o (dec)
Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
34 90o (dec)
Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
35 90o (dec)
Declination is like latitude.
Declination uses () and (-) to denote
positions north and south of the Celestial
Equator.
0o (dec)
- 90o (dec)
36Right Ascension
37Right Ascension is like longitude.
38Right Ascension is like longitude.
Positions are measured in hours and minutes in
one direction only
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40- By convention, the great circle with right
ascension of 0 hours runs through a point in the
constellation Pisces at which the ecliptic
crosses the celestial equator, and right
ascension increases going eastward
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466h
476h
486h
496h
506h
516h
5212h
6h
5312h
6h
5412h
6h
5512h
6h
5612h
6h
5712h
6h
5818h
12h
6h
5918h
12h
6h
6018h
12h
6h
6118h
12h
6h
6218h
12h
6h
6318h
12h
6h
6418h
0h
12h
6h
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66Using both Declination and Right Ascension
67Using both Declination and Right Ascension
any star can be located on the Celestial Sphere.
68For Example
69For Example
A star like Rigel
70For Example
A star like Rigel is found at
71For Example
A star like Rigel is found at
- 8o 11 (dec)
72For Example
A star like Rigel is found at
- 8o 11 (dec)
5 h 15 (RA)
73For Example
A star like Rigel is found at
- 8o 11 (dec)
5 h 15 (RA)
74For Example
A star like Rigel is found at
- 8o 11 (dec)
5 h 15 (RA)
75For Example
A star like Rigel is found at
- 8o 11 (dec)
5 h 15 (RA)
76For Example
A star like Rigel is found at
- 8o 11 (dec)
5 h 15 (RA)
77Good To Know
- The right ascension and declination of each star
are fixed from day to day and year to year. But
because the Earth is wobbling in space because of
the gravitational influence of the Moon and Sun,
the coordinates of celestial objects change over
the course of decades. Every 50 years or so,
star maps and star coordinates are updated.
Current star maps are accurate as of the year
2000.