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by G. Sanjith October 21, 2004 |
Think that stellar astronomy cannot be done with a small telescope or a pair of binoculars? Think the study of stars is best left to professional astronomers? Think again. |
INTRODUCTION:
Stars are an integral part of the universe. There are very prominent in the night sky only next to the moon. But even people with a small telescope prefer to observe the moon rather than stars. They think that real stellar astronomy can't be done with a small telescope but the fact is even a good pair of binoculars would do. The immediate question that arises is "How?".
That is what this article ventures to explain. Also, telescope optics required for good stellar observation is provided.
TEMPERATURE OF A STAR:
There are different parameters of a star. One of them is its temperature. The temperature of a star can be found out easily by simple observations. The colour of a star and its temperature are related. Once the colour of a star is known, its temperature can be found by using some laws such as Wiens Law.
STAR COLOUR | STAR TEMPERATURE (K) |
---|---|
Strong blue | 40000 |
Light blue | 18000 |
Bluish white | 10000 |
White | 7000 |
Yellow-white | 5500 |
Orange | 4000 |
Red | 3000 |
SPECTRAL CLASS:
All the stars in this universe are divided in to spectral classes based on their spectral lines. There are 10 spectral classes. The spectral class of a star and the temperature of a star are related. So the spectral class can be found for a star since we know its temperature. The ten spectral classes are:
O, B, A, F, G, K, M, R, N, S.
TEMPERATURE(K) | SPECTRAL CLASS |
---|---|
50000 | O |
25000 | B |
11000 | A |
7600 | F |
6000 | G |
5100 | K |
3600 | M |
3000 | R, N, S |
The spectral classes are based on the spectrum lines of the star. So, the elements present in the star can be known once the spectral class is known.
TELESCOPE OPTICS FOR STELLAR OBSERVATION:
There are different types of stars in the universe. We shall broadly classify them into two:
CONCLUSION:
This article was written with the aim that people should not think that stellar astronomy is something beyond them and not be content with identifying constellations and gazing at them. All the parameters of stars have not been covered here. Many like magnitude and stellar distance have
been left out. The reader can devise some innovative methods to measure these parameters as well.
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