CTIO 4m Echelle Spectrograph Exposure Time Calculator
Click on button to change device setting, on device name for HELP.
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GG 385
GG 495
RG 610
KG 1
CuSO4
1.0 ND
2.5 ND
Slit width
"
Decker height
3.3
6.6
9.8
13.1
16.4
19.7
26.2
39.4
52.5
65.5
78.7
91.8
105.
118.
131.
341.
"
Folding Flat & Collimator
Blue
Red
Echelle Grating
79.0
31.6
l/mm
Cross Disperser
(l/mm, order, blaze)
G250 158 1 4000
G400 158 1 8000
G226-3 226 1 6300
G226-2 226 1 8000
G510 300 1 10000
KPGL2 316 1 4400
G181 316 1 7500
KPGL3 527 1 5500
G420 600 1 8000
KPGL1 632 1 4200
KPGLF 632 1 8200
G450 632 1 11000
KPGLD 790 1 8500
KPGLG 860 1 10000
G380 1200 1 8000
G226-2 226 2 4000
G510 300 2 5000
G181 316 2 3750
G420 600 2 4000
KPGLG 860 2 5000
G380 1200 2 4000
Mirror 0 0 0
Camera/CCD
Blue Long/Tek2048
Red Long/Tek2048
Folded/Tek1024
Air Schmidt/Loral3K
CCD Binning
(Dispersion)
CCD Binning
(Cross-Dispersion)
Seeing
"
Airmass
Moon
Bright
Grey
Dark
Wavelength
Å
Source flux
Flux Units:
Magnitudes
(Johnson)
Max Exposure Time
sec
AB
(Monochromatic magnitudes)
Total Integration Time
sec
Flambda
(ergs/s/cm²/Å)
Desired S/N ratio
per pixel
Fnu
(ergs/s/cm²/Hz)
Calculate S/N for specified Total Integration Time
Calculate Total Integration Time to reach Desired S/N
mkeane@noao.edu