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Here is a lower quality jpeg of the spectrum:

• After entering a number in the textfields, hit the return key or the show button to make the spectrum appear.
• Click on any position in the spectrum will display the wavelength just left to the show button
• Please note that for the solar spectrum image, it is not possible to change some of the parameters ...

If you want to use the applet on one of your web pages, here are some helpful information:

The element, wavelength range and line width are all controlled by applet parameter (PARAM) tags in the HTML source for this page. There are other options such as width and height of spectra in pixels and contrast which can also be controlled. There are also options to overlay a continuous spectrum of varying strength and to choose the wavelength range. But note that the data sets I use here contain only lines in the 4000 to 7000 Å range
For example here are the parameters for Neon :

<APPLET CODE=discharge.class WIDTH=600 HEIGHT=200>
<PARAM NAME=version VALUE=0>
<PARAM NAME=eye VALUE=0>
<PARAM NAME=element VALUE=neon.txt>
<PARAM NAME=startWavelength VALUE=4000>
<PARAM NAME=endWavelength VALUE=7000>
<PARAM NAME=lineWidth VALUE=2.5>
<PARAM NAME=contrast VALUE=10>
<PARAM NAME=continuum VALUE=0.3>
</APPLET>

• Version:
  • Value = 0: show only the spectrum of the element
  • Value = 1: the full applet with the controls tha permit the user to change any parameter
  • Value = 2: show only the spectrum of the element, but without the wavelength scale
• Eye:
  • Value = 0: this is how a young person with normal vision perceives the spectral colours
  • Value = 1: this is how I - at an age of 59 - perceive the colours. Note that I can no longer look much more blueward than Hg...
  • Value = 2: this is how a person with yellow-green colour blindness perceives the colours. I had asked a student to describe at which wavelengths he perceives different colours, when looking at white sunlight through a spectroscope.
  • Value = 3: just a black and white view, as if we could see well at all wavelengths

• Contrast:
  • Range: 1 to 10000 (the upper limit comes from intensity of the weakest line)
  • Default: 1 (maximum of strongest line assigned to maximum intensity, no distortion of line profile)
  • Increase this parameter to bring up the weaker lines. Of course, one burns out the strongest lines and also the relative difference between the various emission line strengths is lost. Find a compromise to get a pleasing impression -- this applet was not designed to allow accurate intensity measurements.
• Line Width:
  • Range: 0 to 100
  • Default: 3
  • The width of emission lines can be set by the user so that the line profile covers at least one pixel: too small a width causes undersampling to occur and some lines may disappear! However too broad a line will cause blending of lines that are closer together. Again, a compromise must be reached.
• Continuum:
  • Range: 0 to 1
  • Default: 0.3
  • Physics: Apart from the line emission, there often is also a broadband background light, for instance by scattering from an external white source or internal transitions involving the ion continuum. This causes a smooth background to appear as faint 'rainbow'. Here, we merely use it as a pleasing coloured background to fill in the dark gaps between the lines.

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last update: 21 June 2007 J.Köppen