HIRES Exposure Time Calculator

Computing Limiting Magnitude and Limiting Surface Brightness

version 2.0


Program description


Main Input Parameters

λ (μm) [0.35-2.5]
Exposure Time (sec)
NDIT (number of separate read outs to reach the exposure time)
S/N ratio
Diameter of spectrograph aperture (arcsec on sky) (use -1 for default values)

Other Input Parameters

Instrument Efficiency
Telescope Efficiency (use -1 for values released by ESO)
Sky Background (AB mag/arcsec2) (use -1 for default values)
Telescope and optics temperature (K)
Telescope and optics emissivity
Telescope Diamater (m)
Central obscuration fractional diameter
Slit Efficiency (fraction of object-light falling in the spectrometer aperture: use -1 for values released by ESO)
Pixel size (μm)
Focal aperture of camera
On-chip binning (total number of pixels, only for &lambda < 0.95 μm)
Detector Read Out Noise (e-/px)
Detector Dark Current [e-/px/hr]