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1

Db, alias decibel, is a logarithmic unit and can it can measure power or amplitude. This time it measures probably amplitude. The logarithmicity of the unit means in this sense, that if you give 10 to the dB, you get 3.162 times bigger amplitude. If you give 20 to it, you get 10 times higher amplitude. Multiplying the dB value with anything doesn't have ...


9

In astronomy, the background from the camera itself is called "dark current" and is removed by first taking an exposure with the shutter closed for, say, half an hour, and then subtract those counts from the real observations, normalized to the exposure time of a given image. Sometimes, if you're bored at the telescope due to bad weather, you can even take ...


10

By comparing the signal to the background. Suppose you get 10 IR photons from the camera and lens background but an extra 5 from the source then you can still detect the source. There is a whole science of signal processing to detect signals much fainter than the background. Especially in IR astronomy.


5

Interesting. In your title you say "background noise." So I was going to suggest the sea shell effect - putting a sea shell to your ear you think you hear the sea, even if it is far away. If you did think you heard music, that could have been an illusion. Your brain is wired to look for patterns - see animal shapes in the clouds, hear people talking (or ...



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