EFOSC2 Exposure Time Calculator

Optical Spectroscopy Mode Version 6.2.0
The page is loading... please wait!

Target Input Flux Distribution

Template Spectrum Redshift
z =
Target Magnitude and Mag.System:   
= Vega
Magnitudes are given per arcsec2 for extended sources
MARCS Stellar Model
Upload Spectrum
Blackbody Temperature: K
Power Law Index:           F(λ) ∝ λindex
Emission Line
Lambda: nm
Flux: 10-16 ergs/s/cm2 (per arcsec2 for extended sources)
FWHM: nm

Spatial Distribution: Point Source Extended Source

Sky Conditions

Moon phase: days from new Moon
Seeing/Image Quality:
For point sources, the resulting Image Quality FWHM is approximated by a gaussian in the ETC considering the transfer functions of the atmosphere, telescope and instrument. See the helpfile for details.
Seeing: arcsec FWHM in V-band at zenith (use this value in the proposal)
              Probability ---% of realising the seeing ≤ 0.80 arcsec
IQ: arcsec FWHM at the airmass and wavelength of observation (to be used for the OB constraint set)
              The corresponding seeing and probability will be indicated in the ETC output page
Image Quality is not a parameter in AO modes

Instrumental Setup

Slit width:
Detector: CCD#40 Readout mode: Binning: (spectral)×(spatial)
Polarimetry Mode: No polarimetry Linear polarisation


Exposure Time: s

Plots: Toggle All / No Plots

Observed Object+Sky Spectrum
Observed Object Spectrum
Sky Radiance Spectrum in physical units (ph/s/m2/micron/arcsec2)
Observed Sky Spectrum
Sky Transmission spectrum
Total Efficiency and Wavelength Range
Input spectrum in physical units
2D simulated image