- A group of stars which form a recognizable pattern or shape is called a constellation .
- Astronomers have divided the whole sky into 88 constellations.
- Each constellation is assigned a name of the object to which it resembles closely .
- In ancient times the constellation were known as Nakshatras.
Let Us learn more about constellation
- Ursa Major or Big Dipper Vrihat Saptarshi
- It consists of 7 bright stars resembling the shape of big bear
- It also resembles as a question mark
- It also resembles a s kite having long tail
- The Front 4 stars Phecda,Merak,Megrez,Dubhe Represent the body.
- The Other 3 stars represent Tail of the big bear
- The other faint stars form paws and head of the big bear.
2. Ursa Minor or Lahgu Saptarshi or Dhruva Matsaya
- it is also a constellation of group of seven star similar to that of Ursa Major
- The stars are closer and dimmer
- They form an outline of a ladle or kite
- Ursa Minor is a star of average brightness and is called Polaris or Pole Star or Dhrub Tara .
- It is clearly seen in the northern sky in July summer
How to locate the pole star
- Look Straight at the far end of the adle in Ursa Major.The star of medium brightness in the above of these stars is Pole Star.
3. Orion or Hunter or Mriga or Byadha
- It is another constellation of 7 stars
- it is usually seen in winter sky
- The Seven major stars look like a body of a hunter
- Head and limps are formed by faint stars
- Betelguese is the largest star and Rigel is another Brightest star in this constellation
- The Brightest star among all other stars in the Solar system Sirius is a part of this constellation
- It looks a distorted M or W formed by five stars .
- It is visible in winter in the early part of the night
Note- The Name of the Zodiac Signs are actually the name of Constellation.
Above is the Image of the Aries Constellation
- The Moon is the only natural satellite of the earth and is our nearest neighbor in the space
- The Surface of the moon is made up of Large Craters . and has very high mountains
- Moon has no atmosphere hence no life exist on it
- The moon always present its same face towards the earth.
- on the day side its temperature is around 110 degree centigrade
- at night side it may go below -150 degree centigrade
Phases of the moon –
- The Moon is a non luminous body .(it does not have its own light)
- it only reflects the light falling on its surface
- When this reflected light reaches the earth ,we see the moon.
- only that part of the moon is visible,which reflect the sunlight towards the earth
- The Moon Revolves around the earth in a fixed orbit.
- On New moon day the moon is between the sun and earth. hence light reflected from the moon does not reach earth.
- The Night just after the New moon day , we see crescent moon.
- The rest of the moon is faintly visible
- The crescent goes on increasing every day ,till in the fifteen day full moon comes.
- After full moon the ,the brightness goes on decreasing every night.
- This decreasing phase is called waning phase.
The waxing and waning of the disc of the moon ,as the moon revolves around the earth is called phases of the moon.
- The moon completes one revolution around the earth in 27 1/3 days .
- It takes exactly the same time to spin around its own axis.
- due to the same time for rotation on its axis and revolution around the earth hence presents the same face towards the earth.
- How ever as the earths also rotating from the earth moon appears to complete one revolution around the earth in 29 1/2 days
- Lunar calendars are based on the idea that moon completes revolution the earth in 29 1/2 days .
Now Answer these Questions to hone your understanding.