The following spectra are taken using the Science Surplus DIY Spectrometer:
The spectra are from a RELCO fluorescent starter – this contains a neon bulb and in previous posts I have described how I modified this to create a calibration light for my spectrometers:
The neon bulb from the RELCO starter is much fainter than the Compact Fluorescent Light I have used previously. I needed to strap the fibre optic cable close to the neon bulb and point it directly at the bulb and also integrate the light collection over 5000ms.
Fibre optic cable and neon bulb from RELCO starter:
Settings on Spectrum Studio softeware (software that comes with the Science Surplus DIY Spectrometer) showing 5000ms integration time:
The following spectrum is from a Compact Fluorescent ceiling light in the same room – this is to demonstrate that the DIY Spectrometer is working as expected and was taken tonight immediately before the spectra that follow it:
Inverting the colours on above image (using https://pinetools.com/invert-image-colors):
The next two spectra are from the fibre optic cable pointed at the RELCO neon bulb.
Baseline spectrum with the neon bulb SWITCHED OFF:
We think that the lines above are due to hot pixels on the sensor integrated in the DIY Spectrometer or possibly dust in the slit. Note that these lines essentially disappear on the next spectrum – this is due to fact that the scale on the y-axis is quite different between the two graphs = the lines above look large but only because of the y-axis scale and in the spectrum below they are swamped by the much stronger emission lines from the RELCO starter bulb.
Spectrum with the neon bulb SWITCHED ON (so this is the spectrum of the neon bulb from the RELCO starter – neon normally only fluoresces in the red area of the spectrum but the reason these bulbs are recommended by the amateur community is that this particular brand and model contains argon as well giving lines lower down (to the left on the graph – in fact the range covered by this spectrometer at the moment precludes seeing lines in the red so we are seeing them below in blue and green and orange):
Inverting colours on above image (using https://pinetools.com/invert-image-colors):
My next challenge is to identify the lines. There is a very useful document available at http://www.ursusmajor.ch/downloads/sques-relco-sc480-calibration-lines-5.0.pdf to help me do that. The following post on Stargazers Lounge gives some pointers that might help me https://stargazerslounge.com/topic/211549-argon-lines-id-please/
More precise information on the lines in these spectra is available in these 2 data files from Spectrum Studio (these are the data files that underpin the graphs above):
My first attempt at matching the lines in the above spectrum to their frequencies can be found on the following post: