Constellation,Moon and its Phases


  • 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

  1. 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

Ursa Minor – The Little Dipper & Polaris
  • 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.

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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

Related image


  • It looks a distorted M or W formed by five stars .
  • It is visible in winter in the early part of the night

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Note- The Name of the Zodiac Signs are actually the name of Constellation.

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Above is the Image of the Aries Constellation


The Moon

  • 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

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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.


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