Night Sky Bright Star Guide Astronomy Beginners
Night Sky Bright Star Guide Astronomy Beginners
Night Sky Bright Star Guide Astronomy Beginners
The Bright Stars in the Night Sky
About twenty of the brightest stars in the sky are known as first magnitude stars, not that they are all nearer, but are brighter, and sometimes larger than the average star size.
Some sixty of the next brightest are of the second magnitude, and so on with increasing stars as we go up in magnitude (ie go down in star brightness).
There are about eight star magnitudes embraced within the range of the naked eye, two grades having been added above the old first magnitude.
Brightness Rating of Stars
Just like we rate light bulbs, stars are rated according to their brightness. The highest, or brightest, is the negative first magnitude (or -1). Then comes the zero magnitude (0), and below that follow, in order, the first, second, third, fourth, fifth, and sixth magnitudes. Between one magnitude and its next neighbor the difference in brightness is approximately two-and-a-half times (accurately, 2.512).
For example, a star of the first magnitude is two-and-a-half times as bright as one of the second magnitude, six-and-a quarter times as bright as one of the third mag nitude (2.5 x 2.5 = 6.25), and so on, a sixth-magnitude star having only one-one-hundredth as much light as a first-magnitude one.
Stars of the first magnitude are Aldebaran and Altair. The zero magnitude is two-and-a-half times as bright as the first magnitude. Arcturus is a representative of this rank.
The negative first magnitude, two-and-a-half times brighter yet, has but one member, the majestic Sirius, and even Sirius exceeds the ideal standard of his own rank, his .actual magnitude being 1.4. The actual brilliance of Sirius exceeds that of a standard first-magnitude star about nine times. Next to Sirius in brightness is Canopus, in the Southern Hemisphere, invisible from most of the United States.
Viewing Bright Stars - How Many Stars Can I See?
Stars dimmer than the sixth magnitude are not easily visible to the naked eye, but a binocular can reveal up to the 10th magnitude (or more depending on size), and a telescope reveals them up to the thirteenth magnitude or higher (or more depending on size). Also of importance is the seeing conditions, or light pollution of the viewing / observing site. The limiting magnitude is the faintest star that can be seen at that time for that location and has an important effect on ability to see even bright stars, and definitely deep sky objects as well. If you have observed during a full moon, you will notice that the stars are washed out from the brightness of the moon and are difficult to see during these times.
The size, in fact the aperture of the telescope (or binoculars) stated often in inches will determine the amount of stars seen and their magnitude (limiting magnitude).
Bright Star Names
The ancient astronomers gave wonderful names to many of the brighter stars, however modem astronomers have adopted the Greek alphabet with the genitive of the Latin name of a constellation.
Therefore Vega, the brightest star in the constellation Lyra, is cailed Alpha Lyrae, and Riegel, the second brightest in Orion, is called Beta Orionis.
Constellation Star Brightness
The stars are also named in order of brightness in constellations by the Greek alphabet. Thus the brightest star is alpha, the second brightest beta and so on.
How to Find Bright Stars will be covered in the next guide! Stay tuned :)
Bob