Chapter 1
Name: ___________________________________________
Celestial Sphere Worksheet
Part A: Use figure A and B to help answer the following questions
1.
What is right ascension?
 the astronomical equivalent of longitude, the angular distance of an object
2.
What is right ascension is measured in?
 Usually measured in hours, minutes, and seconds with 24 hours being a full circle = 360
3.
What is declination?
 The angular distance of a point north or south of the celestial equator.
4.
What is declination measure in?
 Measured as degrees north or south of the celestial equator.
5.
What is the right ascension and declination for the vernal equinox?
 At the moment of the vernal equinox the Sun's celestial coordinates are 0 hours of RA and 0°
declination.
6.
If the autumn equinox is 6 month later what would be the right ascension and declination for it?
(hint it is half way around the globe)
 Ascension = 12 hours, declination is at 0 degrees. The sun rises at 90 degrees azimuth and
sets at 270 degrees azimuth
7.
What is the declination for the North Pole? The South Pole?
 +90° declination marks the north celestial pole, 0° the celestial equator, and -90° the south
celestial pole.
8.
What is the right ascension and declination for star A?
 The ascension is 8 hours with a declination of 20 degrees
9.
What is right ascension and declination for star B

The right ascension is -20 hours with a declination of 30 degrees
Star B
Chapter 1
Name: ___________________________________________
Star A
Part B Using figures C and D answer the following questions.
1.
What is the declination for the Celestial Equator?
 The declination is 0
2.
How many hours apart is each line of right ascension?
 The are two hours apart each
3.
The winter Solstice occurs at what declination and right ascension?
 At declination -23.5 and right ascension of 18 hours
4.
The summer Solstice occurs 6 months later, what is the declination and right ascensions for it?
 The declination is +20 degrees, and a right ascension of 6 hours
5.
The sun is at the lowest point on the celestial sphere during the (winter, summer) solstice.
6.
The sun is at the highest point on the celestial sphere during the (winter, summer) solstice.
7.
Looking at figure D match the position of the sun with the correct letter.
a. Summer Solstice
b.
Winter Solstice
c.
Equinox
8.
Looking at figure D, the sun is rising in the east and setting in the west.
9.
On figure D label the following
a. Polaris
b. Zenith to the observer
Chapter 1
Name: ___________________________________________