What is the efficiency of the Goodman Spectrograph?

      Total system efficiency (telescope + spectrograph + detector)  exceeds 30% in the visible.  In imaging mode the total efficiency is still being characterized, but it appears to range from 1.15 (B) to 1.7 (R) times higher than the SOAR Optical Imager.

What is the radial velocity stability of the Goodman Spectrograph?

      The spectrograph rotates in the Nasmyth cage, so its RV capabilities are not as good as a bench mounted instrument.  With the highest resolution grating currently available, it has obtained velocities with error bars of about 5 km/s.

Why is there no slit viewing camera?

      It was not possible to fit a camera into the design and one would not work in multi-object mode anyway.  Instead, stars are centered on the slit by using imaging mode to take an image through the slit.  During observations, an autoguider keeps the stars on the slit to within the effects of differential refraction in the atmosphere.

How do I get the best radial velocities?

      Please see the published guidelines here.