New observation and firstime supernova for me ! A light coming from 20 millons Ly !

At V mag nearly 10.5, this SN is in the range of both low and high resolution amateur spectroscopy. Cause of the doppler broadening effect, the spectral lines are very large and oversize my spectral domain, here around HeII 4686A.

But tiny lines in the spectrum maybe insterstellar and intergalactic (!) absorption useful to calculate the extinction of the supernova and then the true brightness and distance (Diffuse interstellar bands (DIB): co-planar doubly excited He and metal atoms embedded in Rydberg Matter

An international amateur campaign is covering this extraordinary event

an insteresting website in doing spectroscopy on the SN

The spectrum was taken with a CN212 telescope (212mm F/D10) and a LhiresIII spectrocope with a 2400 l/mm grate and a 35µm slit, The calibration was made on a Filly lamp with four Xe lines, resolution calculated on the calibration lines is around 8000. The spectral domain is center on 4686, HeII line without doppler effect. The spectra was dark current corrected and flat field (tungsten 2700°k) divided. No instrumental response was applied. A cosmetic correction, due to cosmic rays, was applied between 4671.349A and 4673.693A.

Next step is for me to use my echelle spectroscope and SC14 to capture the whole spectrum at an average resolution of 10000.

Guiding cam and spectra capture during the night :


Spectra 2D, reduction by Spc_Audace (


Final profile, relative flux instensity rescale at 1 around 4680


Fit file spectra: _SN2011fe_4686_20110920_795