1999 Oct 8: Rotating the grating carousel [via an external lever] from the hi-res 600 l/mm grating to lo-res 150 l/mm grating increases the brightness of the spectra permitting short exposures on fainter stars especially when coupled to pixel binning. The complete visual spectrum from ~390nm - 700nm can now be contained on the ST-7 chip width. [Note the larger ST-8 camera chip does not cover a longer spectrum as the spectrometer is designed to match the ST-7's 765 x 9 micron pixels across the width of the chip].
The following selection of essentially raw images were taken in lo-res mode plus 3x3 pixel binning or 27micron 'pixels' giving a dispersion of ~12A/pixel [1.2nm] and resolution ~24A [2.4nm]. The standard 18 micron slit was used. Sky conditions were poor with haze and drifting cloud but the spectrometer showed good penetrating power even in these circumstances. Note the apparent Ha emission line in WR stars may be due to He II.