We see a large number of stars in the sky every night. Since the ancient times they have helped man in more ways than one. He used to find out direction with the help of the Pole Star. He developed astronomy by studying stars and planets. Man has been trying to know more and more about these stars. Powerful telescopes have been made to provide valuable information about the stars. It is also possible to tell the date with the help of stars. Do you know how?
To find out the date, take a large sheet of paper and draw a circle of at least eight inches in diameter. Divide this circle into twelve equal parts — just as a clock face is divided. On each division of the circle, write the name of each month. At the position of 12’O clock write the month of March. Keeping the usual order of the months, write them anticlockwise. Mark the centre of the circle as ‘North Star’. Imagine that the distance on the circle between each month is divided into 30 smaller divisions.
Take your diagram outdoor on a clear night. Hold it in such a manner that the month of March is at the top. Imagine the diagram in the sky, with the North Star as the centre. Note the location of the Big Dipper. Now draw the Big Dipper on your diagram in the same location as you find it in the sky. Having done this, draw a straight line from the pointer to the North Star. This line will pass through the circle at a point that will indicate the date on which you are making your observation. If the line passes half way between the June and July positions on the circle, it is the day of 15th June. Of course, unless you have drawn a very large circle, it will be difficult to estimate 30 divisions between months on the circle. However, you can come within a few days of the exact date.
The important thing is to note that on the diagram you have made on any particular date at midnight, the pointers are in line with that date on the star calendar. This is how we can find out the date by the stars.