Optical Throughput From Pre-Ship Data

The blue spectroscopic efficiency is summarized in Figure 4: Spectroscopic instrument throughput for the four gratings BL, BM, BH2, and BH3. Does not include telescope and atmosphere.. We note that the small slicer has 5% lower (relative) throughput because of vignetting (unavoidable by design) due the small width of the slices. The instrument throughput meets goal minimum and often achieves the performance goals, except for the BH3 grating, which is underperforming by 25%. Note that for the BH gratings the curve is the superblaze showing the envelope of peak wavelengths for each setting that maximizes the efficiency at that wavelength (typically near but not identical to the central wavelength).

The red SIMULATED spectroscopic efficiency for the 7 red gratings is summarized below. It theoretically includes telescope and atmosphere. The real performance is likely 10-15% lower than the simulation (as was found with the blue side).

Total Throughput From Commissioning Data

Notes on these plots:

• The curve segments show single instant bandpass
• Atmosphere is included, but corrected to 1 airmass
• Telescope response is included (3 reflections)
• Corrected to airmass 0 and for telescope response, the throughput of the instrument is about 0.2 higher
• Any observation below 350 nm or above 560 nm require the blocking filter to be retracted