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2000 Aug 30 - return to the Rainbow grating [placed immediately before the CCD detector] using the MX5c camera for the Wolf-Rayet stars in Cygnus. The spectral class of each star show either nitrogen [WN] or carbon [WC] emission lines dominating with hydrogen lines generally absent.The relative weakness of emission lines usually denotes the presence of a 'cooler' companion binary star without emission lines and the contribution of that star to the spectrum blend. Examples below include WR 133, 138 and 139 with O or B-type companions.
Note the dispersion of the grating is essentially linear extending into the near IR [right] whilst dispersion via the prism [above] is compressed towards the red.
