2000 Jan 16 - A selection from spectra captured this evening at 4A resolution via the lo-res [150 l/mm] grating including the emission line stars Zeta Tau with Sirius for comparison.
1999 Oct 12/13: A long 8 hour session included M42 - the spectrometer resolved its emission line spectrum to near perfection - shown here in the negative for clarity with a full size insert. The main OIII line at 5007A could be snapped in 1 second exposure in hi-res+3x3 binned mode !
In common with most imaging whether CCD or film, bright objects through the effects of irradiation tend to spread into darker areas. The reverse occurs with dark objects on a brighter background [like dark line spectra on a bright continuum] to make, for example, the lines seem 'tighter' or sharper. The extremely narrow emission lines, in an object like M42, can be unforgiving but the spectrometer resolves these lines with commendable sharpness without 'spread'.
In contrast to the narrow emission lines in M42 [and NGC 7662 below] Wolf-Rayet stars have turbulent atmospheres recorded as Doppler broadening of their emission lines. Low-res spectra of a number of WR stars including WR136 can be found via my main homepage.
