CanariCam Exposure Time Calculator(v5.0)

Welcome to the CanariCam/GTC exposure time calculator (ETC). Please, in the four sections of this form select the appropriate astronomical source definition, instrument configuration, observational constraints and details of the observation. We strongly recommend you to visit the help pages before starting to use the ETC.

Help on specific subjects can be found in the corresponding links to 'more info' in each section below.

Click on the calculate button (calculate button) at the bottom of any section to submit the parameters from all the sections to the server. The results are reported in a separate web page that can be resized and printed.

Astronomical source definition

Spatial profile and brightness:

Select a point or extended source profile and the source brightness in some selected filters.
Point source with spatially integrated brightness (e.g. 19.3 mag or 2e-17 W/`m^2`/um)
Extended source having ...
  Gaussian profile with full width half maximum of arcsec and spatially integrated brightness of (e.g. 19.3 mag or 2e-17 W/`m^2`/um)
  Uniform surface brightness (e.g. 21.6 mag / sq arcsec)
with the above brightness normalisation applied in filter
Single Select with Groups

Spectral distribution:

Select the object's type of SED and the redshift.
Library spectrum of a non-stellar object
Single emission line at wavelength of um with line flux and line width of km/s on a flat (in wavelength) continuum with a flux density of
Model black body spectrum with temperature K
Model power-law spectrum (S_lambda = lambda ^ )
User-defined spectrum read from file (size < 1MB)
with the spectrum mapped to a redshift z = or a radial velocity v = km/s

CanariCam configuration

Observing mode:

Imaging   Spectroscopy   Polarimetry  Spectropolarimetry 

Canaricam optical properties:

Filter: Focal plane mask:

Please, select the slit width

Observing conditions constraints

Select the expected atmospheric conditions and airmass during the observation. ( more info )
Image quality: best 20%-ile 50%-ile 80%-ile any
Sky transparency (cloud cover): best 20%-ile 50%-ile 80%-ile any
Sky transparency (water vapour): best 20%-ile 50%-ile 80%-ile any
Sky background: best 20%-ile 50%-ile 80%-ile any
Typical air mass during observation: 1.0 1.1 1.5 2.0

Observation details

Calculation method:

  Total S/N ratio resulting from an on-source integration time of seconds
  On-source integration time to achieve a S/N ratio of
  On-source integration time to achieve a Polarization Error of %.
  Polarization Error (%) resulting from on source integration time of seconds.

Analysis method:

  Software aperture radius which gives the 'optimum' S/N ratio and ratio and with a sky aperture times the target aperture
  Software aperture of radius (or slit length) arcsec and with a sky aperture times the target aperture


  For spectroscopy, autoscale or specify limits for plotted spectra (lower wavelength um and upper wavelength um)

Last updated August 8, 2014 by Francisco Ramos and Carlos Álvarez
Updated November 27, 2007 by Frank Varosi