The following plot presents the total efficiency of HDS, including the atmosphere and telescope. This plot is also available in postscript format.
This plot presents the efficiencies of the image rotators and atmospheric dispersion corrector (ADC). It too is available in postscript format.
The degradation of NsOpt image rotators (both red & blue) was found
in September 2013 (by the efficiency measurement after the primary
Please be careful to employ image rotators in your program.
Now (1/28/2014), HDS-ETC is including this effect of degradation.