STUDY SUMMARY - IPMU

SUMMARY REPORT
WIDE FIELD FIBER-FED OPTICAL
MULTI-OBJECT SPECTROMETER (WFMOS)
Table 3.12-1: Spectrograph requirements based on the four surveys. The first three rows are a
repeat of the science case. The other rows are derived requirements.
Requirement DELZ DEHZ
GALR
Blue Red
GAHR
Min λ (nm) 630 420 480 818 480
Max λ (nm) 970 670 544 885 680
Resolving power 3500 1500 5000 5000 20000
SRE width (Angstroms) * 2.82 3.63 1.03 1.70 0.29
Number of SREs per spectrum 1488 688 680 412 6897
Number of spectral orders per fiber 1 1 1 1 4
Length of a single spectral order (mm) 80 37 37 22 93
No. of spectrographs required 2.6 1.2 1.2 0.7 3.0
% of detector area used 86.3% 39.9% 36.3% 22.8% 100%
* SRE – Spectral Resolution Element
Table 3.12-2: Basic derived spectrograph parameters. These are driven by the GAHR survey,
which is the most demanding of the four surveys.
Detector format for one spectrograph
Format of a single CCD
Number of spectrographs 3
93 mm × 93 mm
93 mm × 46.5 mm, buttable along the long side
Collimator f-ratio
Camera f-ratio
Minimum beam size
Fiber pitch at slit
Projected fiber size at detector
f/2.12
f/1.07
~300-mm diameter
230 µm, center to center
54-µm diameter
SRE* width (µm at detector) 54.0 µm
SRE height (µm at detector) = projected fiber pitch 116.25 µm
* SRE – Spectral Resolution Element
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