SUPERNOVA sn2004dj IN NGC2403
7th Aug 2004
VC200L at f6.3 + Vesta SC3 webcam + 100 l/mm grating at 36 A/pixel 34x30sec
At mag +12, the brightest supernova for some time. (clearly visible in the eyepiece, even though the host galaxy was barely evident)
A rather noisy spectrum because of hazy conditions and a bright summer sky but the clear Hydrogen alpha emission line shows that this is a type II supernova - a massive star which exploded when the core ran out of fuel and collapsed.
IMPROVED SPECTRUM 13 Aug 2004
I have used my more sensitive 1004x camera and increased the grating to CCD distance to produce a higher resolution spectrum with less noise .
VC200L at f6.3 + 1004x-JG camera + 100 l/mm grating at 18.6 A/pixel 34x30sec
Also shown on this plot for comparison is a spectrum from another type II supernova sn1992h (from this sourcehttp://www.astro.rug.nl/~onderwys/ACTUEELONDERZOEK/JAAR2001/rico/spectra.html ) The detailed similarity is remarkable, giving me confidence that I am producing valid spectra (The broad hump shape of my spectrum comes from the spectral response curve of the CCD which has not been corrected for)
The characteristic H alpha emission line and blue shifted absorption line is clear. I have also tentatively identified other lines in the Balmer series. The 2.5% blue shift corresponds to a velocity of approximately 7500km for the expanding shell of gas
CLICK HERE FOR AN IMAGE OF THE SUPERNOVA AND GALAXY
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