Astronomy: Reading a Star Map and Finding Constellations
Use directions, star brightness, and patterns to locate constellations
Astronomy: Reading a Star Map and Finding Constellations
Use directions, star brightness, and patterns to locate constellations
Astronomy - Grade 6-8
- 1
A star map has north at the top, south at the bottom, east on the left, and west on the right. If a constellation is shown near the top of the map, which direction should you face to look for it in the sky?
Use the direction labels on the edge of the star map.
You should face north because the top of the star map represents the northern part of the sky. - 2
On many star maps, larger dots show brighter stars and smaller dots show dimmer stars. If a constellation has one very large dot and several small dots, what does that tell you about the stars in that constellation?
The very large dot represents a bright star, and the smaller dots represent dimmer stars in the same constellation. - 3
The Big Dipper is part of the constellation Ursa Major. Its two outer bowl stars are often called pointer stars because they point toward Polaris, the North Star. If you find the Big Dipper low in the northern sky, how can you use it to find Polaris?
Start with the two stars on the side of the bowl farthest from the handle.
You can draw an imaginary line through the two outer stars of the Big Dipper's bowl and continue that line until you reach Polaris. - 4
A star map is labeled for 9:00 p.m. on March 15. Why might the same map not match the sky perfectly at 9:00 p.m. on July 15?
Think about how Earth's position changes during the year.
The same map might not match because different constellations are visible at different times of year as Earth orbits the Sun. - 5
A student sees Orion near the southern horizon on a winter evening. On a star map, Orion is also shown near the southern edge. Explain why this is a good match between the map and the sky.
This is a good match because the constellation appears in the same direction on the map and in the real sky. The southern edge of the map corresponds to the southern horizon. - 6
A constellation is shown halfway between the center of a circular star map and the outer edge. What does this suggest about the constellation's height in the sky?
On a circular star map, the center usually represents the sky overhead and the outer edge represents the horizon.
The constellation is at a medium height in the sky. It is higher than the horizon but not directly overhead. - 7
On a clear night, you identify three bright stars in a straight line. A star map shows that these three stars are Orion's Belt. What should you look for nearby to confirm that you have found Orion?
A constellation is identified by the whole pattern, not only one part of it.
You should look for the rest of Orion's pattern, including bright stars above and below the belt that form the hunter shape. - 8
A star map shows Cassiopeia as a W-shaped pattern in the northern sky. If you see a W-shaped group of bright stars above the northern horizon, what is a reasonable conclusion?
A reasonable conclusion is that the W-shaped group may be Cassiopeia, especially if it is in the northern part of the sky as the map shows. - 9
Why should you turn a printed star map so that the direction you are facing is at the bottom of the map?
The bottom of the map should match the horizon you are looking toward.
You should turn the map that way because it helps the map line up with the sky in front of you, making it easier to match star patterns. - 10
A star map shows Vega high in the eastern sky and Deneb lower in the northeast. A student faces east and finds a very bright star high above the horizon. Which star is the student most likely seeing, and why?
The student is most likely seeing Vega because the map places Vega high in the eastern sky, matching the student's observation. - 11
Two stars on a map are close together, but when you look at the sky, they seem farther apart than expected. Give one possible reason for this difference.
A star map is a model of the sky, not the same size as the sky.
One possible reason is that the map is smaller than the real sky, so distances are compressed. Another possible reason is that the student may not be using the correct time, date, or direction. - 12
Use this observing plan: first face north, then find the Big Dipper, then use its pointer stars to locate Polaris, then look for Cassiopeia on the opposite side of Polaris from the Big Dipper. Explain why this plan is useful for finding constellations.
This plan is useful because it starts with a familiar pattern, uses Polaris as a reliable reference point in the northern sky, and then uses relative positions to find another constellation.