Spectrograph 2.0

I'm going to have to take a photo of my setup later/tomorrow, but for now I really want to share a recent project. I've been working on collecting different light sources and then using diffraction grating to break the light up, and then trying to photograph it.

Without going into too much detail, the cool thing about this is you can identify specific elements by their emission lights, and the same technique is used to identify the constituents of our sun and other stars in the galaxy. We also use similar techniques where I work to determine the make-up of the various metal alloys we work with.

So, without much further ado, here's a composite photograph of the spectra I've captured with my 40D, 70-200 @ 200mm, f/32, ISO800 (seems to help with defining the lines), and various Tv speeds to get the right balance of spectral lines. Of course on a tripod.

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Cool! I'd love to see a pic of your setup...

I LOVE LOVE LOVE this type of stuff. I am really into astronomy, and continuously am amazed how they are able to use the spectrum to find out the composition of different heavenly bodies. And I too would LOVE to see your setup!

Okay, here's the setup (crappy iPhone pics, sorry) and an updated chart. Basically, the light source exits a thin slit, about 30 degrees relative to the camera's view, and then it hits the diffraction grating (1000 lines/mm in this case). The dark matboard is just to get a nice even dark background. I adjust shutter, etc as needed.

I am hoping to get some Sodium vapor lights and possible some other "foreign" lights such as Argon or Xenon soon.

I tried a sterno can, which burns methanol alcohol, but that didn't do much. I added table salt and it definitely brought out the Sodium (Na), and then I tried dishwasher soap (it contains Sodium silicate and Sodium carbonate), but I swear that just gave me a headache. I'll have the consult with the chemists at work Monday on just how stupid I was...

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godzakka wrote in post #9508598
Okay, here's the setup (crappy iPhone pics, sorry) and an updated chart. Basically, the light source exits a thin slit, about 30 degrees relative to the camera's view, and then it hits the diffraction grating (1000 lines/mm in this case). The dark matboard is just to get a nice even dark background. I adjust shutter, etc as needed.

I am hoping to get some Sodium vapor lights and possible some other "foreign" lights such as Argon or Xenon soon.

I tried a sterno can, which burns methanol alcohol, but that didn't do much. I added table salt and it definitely brought out the Sodium (Na), and then I tried dishwasher soap (it contains Sodium silicate and Sodium carbonate), but I swear that just gave me a headache. I'll have the consult with the chemists at work Monday on just how stupid I was...

The sodium silicate isn't the best for you, but the washing soda (sodium carbonate) isn't really a big deal. The sodium silicate causes respiratory irritation (but does not cause cancer or other equally nasty side effects from what I remember). Ventilation is always a good thing if you're working with something that you're unsure of...

On another note though, I really like the setup and will probably try it myself once I have an opportunity. I just need to dig up a source online for a decent grating as I don't the same access to these things after finishing grad school.

Is the f32 to stop down the 800iso? You may get some better pics if you use a ND filter on the lens as f32 will introduce some lens diffraction issues.

Very cool. I've looked at some spectroscopes for gemology use(another thing I like to do), but just couldn't decide if I really wanted to lay out the money for it or not. I didn't realize that I could get a diffraction grating and make my own so easily. Hmmm... Home-made spectroscope, here I come!