The Night Sky



Does the Pole Star have any practical significance?

The Pole Star (Polaris or ‘Dhruva’) helps navigation locate the north direction in the absence of any landmark, even in deserts and oceans. This is also called the “North Star”.










What are the pointer stars or “The Pointers”?

The stars Alpha and Beta (Dubhe and Marak) in the constellation Ursa Major (also known as Great Near, Big Dipper, Plough or “Saptarishi”) are called “The Pointers” since a line drawn through these stars points towards the Pole Star.

Is there any star like Polaris at the South Celestial Pole?

No. However, a group of star known as “Crux” (“Trishanku” or “Southern Cross”) is situated almost at the South Celestial Pole and helps navigators in locating the south direction.










What is the sidereal year?

Assuming the stars to be fixed  in space on the Celestial Sphere, the time taken for the Sun’s projection on the celestial sphere to make one complete revolution of the celestial sphere, is called the sidereal year. This aspect of the solar year is of great importance in astrological calculations.




What is meant by Zenith and Nadir?

Zenith is the uppermost point on the celestial sphere seen vertically above an observer on the Earth’s surface. The point on the celestial sphere diametrically opposite the Zenith is the Nadir.