Spectra of Jupiters Moons
12.5" Newtonian and Star Analyzer
Uploaded 11/7/12

When examining the moons of Jupiter visually, I have always noticed that Io, the volcanic moon with no ice is quite yellow in color compared to either Europa or Callisto which are covered in pure white ice. Since ice reflects the suns G2V spectra they appear white and a repeat of the solar spectrum. Io on the other hand can attribute its yellow color to sulfur compounds on its bare volcanic surface. Visually, I could never see any more on this moon than just a tiny featureless disk. To be able to see some additional details about this moon is a real bonus!

Look carefully at the spectra and you will see that on the blue end, Io is lacking the reflectivity that Europa possesses. This is why it is yellow in color.

Click on these thumbnails for the full size view:
Actual image through 12.5" and Star Analyzer grating with DMK51 CCD camera at prime focus
  In violet - Europa which is pure white ice In Blue - Io, the surface is mostly sulfur
Instrument: 12.5" f/5 Home made Newtonian Grating: Star Analyzer 100 lpmm Mount: Astrophysics 1200 QMD CCD Camera: DMK51 Imaging Source Location: Payson, Arizona, Elevation: 5150 ft. Sky: Seeing FWHM = 4 arcsec , Transparency 9/10 Outside Temperature: 45 F Image Processing Tools: RSpec for spectral extraction, Photoshop CS2 HOME GALAXIES EMISSION NEBS REFLECTION NEBS COMETS GLOBULARS OPEN CLUST PLANETARIES LINKS