KCWI Modes and Instrument Properties
KCWI has a selection of grisms and field slicers to set the spectral resolution and field of view. In addition, there is a deployable nod and shuffle (NAS) mask that blocks the upper and lower thirds of the detector in order to perform observations of faint objects that require background subtraction. The following table, taken from the KCWI Configuration page, summarizes the resultant data properties for the different combinations of the grisms and slicers.
KCWI Slicer and Grating Configurations
|
Slicer |
||||
|---|---|---|---|---|---|
|
Large |
Medium |
Small |
||
|
|| x ⊥ Dispersion |
||||
|
Field of View |
33" x 20.4" |
16.5" x 20.4" |
8.4" x 20.4" |
|
|
Slice Width |
1.35" |
0.69" |
0.35" |
|
|
|
|
|
||
Grating |
Parameter |
Bandpass/Dispersion |
|
|
|
BL |
R (central) |
0.625Å/pixel |
900 |
1800 |
3600 |
|
Δλ (total) |
350-560 nm |
|
|
|
|
Δλ (instantaneous) |
200 nm |
|
|
|
|
Δλ (NAS) |
50 nm |
|
|
|
BM |
R (central) |
0.28Å/pixel |
2000 |
4000 |
8000 |
|
Δλ (total) |
350-550 nm |
|
|
|
|
Δλ (instantaneous) |
80-90 nm |
|
|
|
|
Δλ (NAS) |
20-22 nm |
|
|
|
BH3 |
R (central) |
0.125Å/pixel |
4500 |
9000 |
18,000 |
|
Δλ (total) |
470-560 nm |
|
|
|
|
Δλ (instantaneous) |
47-53 nm |
|
|
|
|
Δλ (NAS) |
12 nm |
|
|
|
BH2 |
R (central) |
0.125Å/pixel |
4500 |
9000 |
18,000 |
|
Δλtotal) |
400-480 nm |
|
|
|
|
Δλ (instantaneous) |
37-44 nm |
|
|
|
|
Δλ (NAS) |
10 nm |
|
|
|
BH1 |
R (central) |
900 |
4500 |
9000 |
18,000 |
|
Δλ (total) |
350-410 nm |
|
|
|
|
Δλ (instantaneous) |
~40 nm |
|
|
|
|
Δλ (NAS) |
~10 nm |
|
|
|
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