Fraunhofer Lines ...

Twinkle, twinkle, little star,
How I wonder what you are!
Up above the world so high,
Like a diamond in the sky!

-- Jane Taylor, "The Star", 1806

Today I happened to notice that the sun was shining through the window and directly onto a spectroscope that was sitting on my bench. I purchased this piece of equipment on eBay several years ago and am now in the process of returning it to working condition. The slit is still a jerry-rigged assembly of masking tape and aluminum foil, but I thought I'd take advantage of the favorable position of the sun to see if I could observe any spectral lines. This is something that I've tried before, but have never successfully accomplished.

After aligning the first telescope with the sun, I positioned the 2nd telescope for viewing and the lines could not have been more obvious. To record the event I grabbed my digital camera (just a little Casio -- nothing particularly fancy) and held it to the eyepiece. The following are some of the spectra that I observed:





I am fairly sure that the doublet in the orange portion of the last (bottom) spectrum is due to sodium (the D lines). Unfortunately there was not enough time to measure the wavelengths of these lines due to the position of the sun (it was only minutes from setting), so I cannot be absolutely sure of their identity. Still, after looking at a diagram I believe that the middle figure (the one that is entirely green) shows some lines from Magnesium (b1 and b2) and Iron (the E line). I am not entirely sure which is which, however. Also, the top figure probably shows the hydrogen-beta line (Fraunhofer F line -- one of the Balmer series lines).

More information on these lines can be found here. There are sites out there with far more detailed databases of solar lines (thousands are known), but this diagram is simple enough for those of us with very basic equipment. A very high resolution spectrum can be obtained from the NOAO (National Optical Astronomy Observatory).

When conditions are more favorable and this instrument is in better condition I will post a more detailed set of observations and some photos of the instrument itself.