I am now reading the book ''The story of Helium and the Birth of Astrophysics''.

I really want to observe the lines (dark or bright) in the solar spectrum.

Any easily available tools for an amateur?


2 Answers 2


Yes, with a piece of 1000 lines / mm of diffraction grating that costs a few dollars, and some odd bits and ends, you could see the Fraunhofer lines.

Here's a way to build it:


At the bottom there's a link to a place where you could purchase diffraction grating - but any grating around 1000 lines / mm is fine, and you could probably find it in other places too, if this store doesn't work for you for some reason.

You could try to use a digital camera and photograph the spectrum, instead of looking at it directly.

Beware, looking into the Sun poses a certain amount of danger. As long as you keep the slit pretty narrow, this spectrograph is safe. If the spectrum is too bright to look at comfortably, the slit is probably too wide and the instrument is not safe for direct viewing (but probably safe for a camera).

You could also use it to inspect other sources of light: LED lightbulbs, fluorescent lamps, open flames, etc. It's quite fascinating.

  • $\begingroup$ so you have one for yourself? $\endgroup$
    – wdlang
    Commented Jun 23, 2014 at 18:21

You need a diffraction grating in order to split the sunlight into a spectrum. It turns out even a normal CD or DVD because of the pits that they have to encode data work very well as high resolution diffraction gratings. You could make a simple enclosure with a CD and a slit like this:


This should allow you to observe the sun's spectrum, although I would also recommend that you be very careful when observing the sun directly. Preferably use a very narrow slit--this will both make it safer and make the absorption lines much clearer.

  • $\begingroup$ You'll struggle to do it, but it is possible with a big cereal box. $\endgroup$
    – ProfRob
    Commented Jun 20, 2016 at 5:16
  • $\begingroup$ It's probably easier with a cardboard tube from a paper towel roll. I have build one myself and it works quite well. $\endgroup$ Commented Jun 20, 2016 at 6:08

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