STUDY SUMMARY - IPMU

SUMMARY REPORT
WIDE FIELD FIBER-FED OPTICAL
MULTI-OBJECT SPECTROMETER (WFMOS)
4.0 Instrument Performance
4.1 Optical Throughput
Throughput is a key parameter as it ultimately governs how quickly observations can be
made. The Optical Throughput allocation, where each element of the design was assigned a
throughput to match or exceed was created and these values are included as requirements in the
FPRD. As requirements, these values represent the minimum performance; the instrument design
strategy is to maximize performance and the Current Best Estimate (CBE) is presented here. As
the instrument design matures, continued improvement is sought through subsystem design
choices and balancing resources throughout the instrument system to maximize total throughput.
The instrument CBE is presented in Table 4.1-1 and is supplemented with the estimated
throughput from external factors such as the telescope primary, the WFC, and atmospheric dispersions.
The instrument performance estimates, also include the variations between the different
surveys. For example, the Dark Energy surveys require a different order sorting filter type from
the Galactic Archaeology surveys and produce a different throughput estimate for each survey
type. The throughput is presented at the wavelength extremes of 420 nm and 970 nm and several
wavelengths in between.
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