Magnitude those things

refers to the relative brightness of stars in the sky.In general, it also refers to the "apparent magnitude", is to see the brightness of the stars from the earth.

magnitude those things

the first set by the Greek astronomer xi pachacutec,, he will be a total of 1025 stars in the sky, the 20 stars as the first one of the most bright stars, and the brightness is only about half of the stars to be classed as second-class star, to the dark sixth magnitude, is almost to the naked eye can see the limit of the dark star.

magnitude those things

hi pachacutec,

this classification in the 2nd century AD, by another astronomer Ptolemy published (Ptolemy), included in the quite important works - Almagest (Almagest) in the book.

magnitude those things

one

in the 16th century, Danish astronomer tycho (TychoBrahe) further "the size of the stars" as the stars of the brightness of the classification, the greater the brighter the stars look.

magnitude those things

tycho

when the telescope was invented, astronomers is to carefully measure the size of the stars to represent its brightness difference.So until the 19th century, the brightness of the stars are still in their "it seems that the size of the" to distinguish between magnitude.

in 1856, English astronomer posen (Norman r. Pogson) found that when using the telescope to observe stars, the greater the telescope, you can see, the dark star.If he will telescope part open cover, dark stars will disappear from view.So he will cover the opening of the telescope, bit by bit the brightness of the comparison between the stars and the star.He found that magnitude difference of five stars, such as brightness are roughly 100 times, he suggested the brightness difference between each magnitude, defined as 1/5 of the power of 100, which is 2.512 times.

but 1 to 6 magnitude cannot describe was found in all the brightness of the object, astronomers extending original level ─ ─ introduce the concept of "negative magnitude".So the apparent magnitude system has been in use today.

让我们一起看看

那些熟悉天体的星等吧

从地球表面上看到的太阳视

星等约为−26.74

星等那些事

从地球上看月亮最亮时

视星等可达到−12.92

星等那些事

从地球上看猎户座参宿四

视星等约为0.42

星等那些事

从地球上看仙女座星系

视星等约为4.36

需要在光污染较少的地区才能被肉眼所见

星等那些事

从地球上看三角座星系

视星等约为5.72—6.3

接近人类肉眼可辨认的极限

星等那些事

从地球上观测后发座NGC 4414

视星等约为11.0

星等那些事

哈勃极深空中

最暗的星系视星等为30

只有肉眼可分辨光度下限的一百亿分之一

星等那些事

图片:维基百科 作者:望天 编辑:虫虫

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