CONSTELLATION

CONSTELLATION

Example Of Constellation

• Big Dipper
• Orion
• Southern Cross
• Scorpion

Importance Of  Constellation

• To Show Direction
• To Show Time Or Season

UNDERSTANDING THE CONSTELLATION

1. When we look into the sky at night,we can see some stars.
2. These Stars produce their own light which makes them visible from the Earth.
3. Thousands of years ago people had observed that groups of stars formed shapes or images.
4. we imagine that lines can be dram joining one star to another to from shapes or images.
5. The arrangements of group of stars which from a certain shapes or image is known as a constellation.
6. Astronomers named the constellation after mythical animals or heroes because the shapes of these constellation look like them.
7. These constellation include Scorpion,Orion,Big Dipper and Southern Cross

Type Of Constellations

1. Constellations can be seen clearly at night when there is no sunlight.
2. They cannot be seen during the day because the sunlight is too bright.
3. Some famous constellations are show in diagrams 17.1
4. The location of constellations in the sky changes from one position to another because the Earth rotates on its own axis.
5. Therefore ,we cannot see all the constellations at the same time.

Orion

Southern Cross

Scorpion

Big Dipper

Diagram 17.1 shows the time of appearance of some constellations.

Constellation      Time of appearance

Big Dipper          April to June.

                           Around 8:00 p.m.

                           -10:00 p.m.

Southern             April to June.

                           Around 8:00 p.m.

                           -10:00 p.m.

Scorpion             June to August

                           Around 8:00 p.m.

                           -10:00 p.m.

Orion                 December to February 

                          Around 8:00 p.m.

                          -10:00 p.m.

Table 17.1 Time of appearance of some constellation

A. Scorpion

1. This constellation looks like a scorpion.

B. Orion

1. This constellation looks like a hunter with a belt and sword
2. Its is visible in both the northern and southern hemispheres.

C. Southern Cross 

1. This constellation look like a cross or a diamond-shape kite.
2. It can be seen only in the southern hemisphere.
3. It is the smallest constellation among the 88 modern constellations.

D. Big Dipper

1. This constellation looks like a saucepan or dipper
2. It is visible only in the northern hemisphere.

The Importance of Constellations

A. To Show direction

1. In ancient times,sailors and explorer used constellations for navigation.
2. For example,the Big dipper can be seen only at the northern hemisphere and it always points to direction of the North Pole.
3. Similarly,the Southern Cross can be seen only at the southern hemisphere and it points to the direction of the South Pole.
4. Astronomers also used the constellations to study the other stars in the Universe.

B. To indicate time (or season)

1. Farmers know that most crops should be planted in the spring and harvested in the autumn.
2. But in some regions,there is not much difference between the seasons.
3. Different constellations are visible at different times of the year.
4. Farmers can make use of the appear of the constellation to tell what month(or season)it is.
5. For example, Scorpion is only visible in the northern hemisphere's evening sky in summer.
6. Some historians believe that many of the myths related to the constellations help the farmers remember them.
7. Example,when they see certain constellations in the night sky,the farmers know that it is the time to being planting or harvesting.

FORMATIVE PRACTICE

SECTION A

Every question is followed by four option A,B,C and D.

Choose the correct answers.

1. Diagram 1 shows an image of a constellation used by astronomers.

Diagram 1

1. What is the name of the constellations?

A. Orion               B. Scorpion

C. Big Dipper       D. Southern Cross

2. What is the name of constellation shown in Diagram 2?

Diagram 2

A. Orion                    B. Ursa Major  

C. Big Dipper           D. Southern Cross

3. Which of the following constellations is only visible in the northern hemisphere?

A. Orion             B. Southern Cross

C.Big Dipper     D. Scorpion

4. Which of the following Constellations is Big Dipper?

Formative Practice 42

Section A
                    1. A       2. D         3. C     4. B    5. A


Section B

                  (a) P: Big Dipper            Q: Orion
                        R: Scorpio                  S: Southern
                         
                  (b)  P
                  (c)  Q,S