Estimated overheads

Table 4 summarizes the time to readout in various modes, the time to move mechanisms, and the estimated overhead time for nod-and-shuffle mode. Colors are light yellow for common mechanisms and light blue/red for respective blue and red sides.

Table 4 : KCWI Instrument Overheads

Operation	Time	Comments
Target acquisition	0.5-5 min	Bright targets are fast, fuzzy smudges are slower
Changing IFU slicer/FPC	60 s between each station	S\|M\|FPC\|L
Blue Grating exchange and rotation	5 minutes	Depends on beginning/end grating
Blue Camera/Detector rotation, happens during the rotation above	~90 s	Depends on angles; useful for a wavelength change with the same grating
Red Grating exchange and rotation	2 minutes	Depends on beginning/end grating
Red Camera/Detector rotation, happens during the rotation above	~30 s	Depends on angles; useful for a wavelength change with the same grating
CAL set script	3 min + exposure times + readouts	move in, calibration exposures, move out
Take the calibration exposure times below and use them as is (1x) for the Large slicer, 2x for the Medium slicer, 16x for the Small Slicer. The calibration script takes each set of exposures together (e.g. 1 blue ThAr arc with 3 red ThAr arcs) and will not move on until all exposures are finished.
Blue Bias	0 s	Blue calibrations take 7
Blue FeAr Arc [BL\|BM\|BH]	10 s \| 20 s \| 40 s	Blue calibrations take 1
Blue ThAr Arc [BL\|BM\|BH]	20 s \| 40 s \| 60 s	Blue calibrations take 1
Blue Continuum Flat [BL\|BM\|BH]	0.5 s \| 1 s \| 3 s	Blue calibrations take 6
Blue Continuum Bars [BL\|BM\|BH]	0.5 s \| 1 s \| 3 s	Blue calibrations take 1
Blue Dome Flat [BL\|BM\|BH]	6 s \| 20 s \| 60 s	Blue calibrations take 3
Red Bias	0 s	Red calibrations take 7
Red FeAr Arc [RL\|RM\|RH]	2.5 s \| 10 s \| 2-150 s	Red calibrations take 3
Red ThAr Arc [RL\|RM\|RH]	2.5 s \| 15 s \| 2-150 s	Red calibrations take 3
Red Continuum Flat [RL\|RM\|RH]	2.5 s \| 5 s \| 10-30 s	Red calibrations take 6
Red Continuum Bars [RL\|RM\|RH]	2.5 s \| 5 s \| 10-30 s	Red calibrations take 3
Red Dome Flat [RL\|RM\|RH]	10 s \| 15-30 s \| 30-100 s	Red calibrations take 3
Blue Single amp slow read, 1x1 [2x2] binning	337 [106] s	Rn=2.7e-
Blue Dual amp slow read, 1x1 [2x2] binning	170 [53] s	Rn=2.7e- (most common mode)
Blue Quad amp slow read, 1x1 [2x2] binning	85 [27] s	DO NOT USE! ESPECIALLY WITH NOD-AND-SHUFFLE!!!
Blue Single amp fast read, 1x1 [2x2] binning	75 [25] s	Rn=5e-, use only for setup
Blue Dual amp fast read,1x1 [2x2] binning	38 [13] s	Rn=5e-, use only for setup
Blue Quad amp fast read, 1x1 [2x2] binning	19 [7] s	Rn=5e-, NOT RECOMMENDED
Red Dual amp pre-exposure erase	13 s	Need to check if varies with binning
Red Dual amp slow read, 1x1 [2x2] binning	90 [30] s	Rn=3e-
NAS overhead	10-20 seconds per nod for settling	Example: A 10 S, 9+1/2+1/2 B NAS with 2 minutes per exposure requires 210120s+21*10s=2610s
NAS setup	TBD	TBD based on commissioning