wpo - more emission line stars
1999 Oct 25: Repeat spectra of two Wolf-Rayet stars in Cygnus together
with P Cygni. Mid resolution is used i.e. low-res 150 l/mm grating plus
9 micron pixels yields 4A/pixel [0.4nm/pixel] dispersion and shown here
full size. Mercury light [Hg] comparison spectra has been added and involves
switching on this lamp remotely from the observatory annexe for a few seconds
during the main exposure. The reference lines to the extreme right [shown
red] are due to argon [Ar] within the mercury lamp envelope.
return to main spectrometer page ..
Repeat spectrum of M42 at 4A/pixel dispersion covers the whole visible
spectrum. Note that Ha is the strongest line
at 656nm in this 'diffuse nebula' illuminated by the Trapezium stars whilst
twin lines of doubly ionized oxygen [OIII] at 500.7nm + 495.9nm typically
predominate in 'planetary nebulae'.
