MOSFIRE *UNVERIFIED* Exposure Time Calculator
Template: JAB: z:
Seeing [as]: Slit [as]: Npix:
Npairs: texp [s]: ttotal:

The following table summarizes the expected spectral resolution R (λ/Δλ), and S/N ratio in the best quartiles (25%, 50%, 75%, and 100%). To get a sense for the number of total detected photons an example wavelength is selected in each band near the median signal-to-noise ratio. Note that the values are summed over exposures assuming Poisson statistics. The total number of photons from the object and sky are computed in a resolution element at the example wavelength. Note that A/B subtraction is assumed and accounted for in the s/n calculation.
Y J H K
Typ. Slit-Limited R:
S/N Quartiles:
λexample:
Detector noise per resolution element includes a read-noise of and dark-current shot-noise of .
Note that Total RN=RNpixel · (Npix · Npairs · 2)1/2

The slit and extraction diameter subtend . Extraction losses for the slit width and seeing amount to .


Plots

Detected Signal to Noise Ratio per Resolution Element
S/N

Detected Photons per resolution element in a single exposure. Bottom horizontal lines indicate total read noise and dark current (in photons). Top horizontal lines indicate where the detector becomes one-percent non linear or saturated.
Counts

Emitted AB Magnitude SED of object and Sky for the given slit and seeing.
The SEDs

Throughput (Sky, Slit, Optics, and Detector)
MOSFIRE's Throughput as a function of wavelength