NCERT Solutions Curiosity Chapter 12 .2 Night Sky Watching — Activity 12.3: Let us try to identify
Book page 23812 Updated on2026-09-05
Q1.
In India, Orion is best viewed during the months of December to April after sunset. So, look for it during that period. Three bright stars in a short straight line are located around the middle of Orion (imagined to be the belt of a hunter). Identify these three stars first, as this is the easiest way to find Orion.
Answer
Observation: between December and April, an hour or two after sunset, look towards the eastern and then the southern sky. You will see three bright stars in a short, straight, almost evenly spaced row — nothing else in the sky looks like this. That row is Orion's belt.
Once you have the belt, the rest of the hunter falls into place around it:
Two bright stars above the belt are the hunter's shoulders. The reddish one is Betelgeuse, called Ārdrā in Indian astronomy.
Two bright stars below the belt are his feet. The brilliant blue-white one is Rigel.
Orion is often shown battling a bull (Taurus), with his dog (Canis Major) following behind.
Orion the hunter: two shoulders, three belt stars in a row, two feet. Extending the belt line leads to Sirius. The lines are imaginary.
Did you know? The belt stars are so evenly spaced and so nearly in a straight line that many Indian villages call them teen tara or the three sisters. They are the easiest starting point in the whole winter sky.
Q2.
Once you identify Orion, it is easy to locate the very bright star Sirius which is located close to Orion. Imagine a straight line passing through the three middle stars of Orion and look along this line towards the east. This will lead to Sirius.
Answer
Method: stretch the line of the three belt stars out beyond the belt, towards the east, and follow it. It runs straight into a fiercely bright, slightly bluish star that clearly outshines everything else around it. That is Sirius.
Sirius is the brightest star in the whole night sky. It belongs to the constellation Canis Major — the hunter's dog. Its Indian name is Lubdhak.
Why it is so bright: two reasons together. Sirius is a genuinely hot, bright star, and it is one of the nearest stars to us. Brightness in the sky always depends on both how much light a star gives out and how far away it is.
Check it yourself: Sirius twinkles very strongly, often flashing red, white and blue when it is low in the sky. This is because it is a point of light and our atmosphere keeps bending its rays. A planet at the same height hardly twinkles — that is a quick way to tell a star from a planet.