A spectroscope is a scientific instrument that splits light into its separate colours so you can look at them. Think of what a glass prism does to sunlight — it opens the white light into a band of colour. A spectroscope does that carefully, with a slit and a prism or a fine grating, so a scientist can see exactly which colours are there and which are missing. Why does that matter? Because every substance, when it burns or glows, gives out its own particular set of colours — a kind of fingerprint. So by looking through a spectroscope at a flame, or at a distant star, you can tell what it is made of. That is how we know what stars are made of without going there, and it is one of the great tricks of science. This is a technical word. You meet it in physics and chemistry class, in astronomy, and in older science writing; it is not conversational. Note the difference between the close cousins: a spectroscope is the INSTRUMENT you look through, and spectroscopy is the whole SUBJECT of doing this. If it makes a permanent photograph or record, it is called a spectrograph. In modern labs the older name is less used — people say spectrometer — but 'spectroscope' is still what textbooks call the basic viewing instrument.

分光鏡、光譜儀。把光分開成各種顏色(光譜)來觀察的儀器；科學家用它判斷物質或星星由什麼元素組成。