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CanariCam Integration Time Calculator

In the four sections of this form, select the appropriate astronomical source, instrument, telescope, observing condition and observation parameters. 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.

General guidance on use of the Integration Time Calculators (ITCs) is available; specific help on each section of the form is available by following the more info and other (blue highlighted) links. Note: at this time Netscape 6 and 6.01 do not work with web forms. Changes, enhancements and bugs within the ITC are listed chronologically.

Astronomical source definition

Spatial profile and brightness:(more info)
Choose one of point, extended or user-defined source profile and the brightness in any filter/wavelength
Point source (nominal PSF) 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)
  disabled Exponential profile with spatially integrated brightness (e.g. 19.3 mag or 2e-17 W/m^2/um) and half-light radius of arcsec (disabled)
  disabled Elliptical r^(1/4) profile with spatially integrated brightness (e.g. 19.3 mag or 2e-17 W/m^2/um) and half-light radius of arcsec (disabled)
disabled User-defined 2D image read from file (disabled)
with the above brightness normalisation applied in filter band or disabled at a wavelength micron (latter option disabled)

Spectral distribution: (more info)
Choose one SED, the redshift and extinction
Library spectrum of a non-stellar object
option disabled Library spectrum of a star with spectral type
option disabled Single emission line at wavelength um with line flux and line width km/s on a flat (in wavelength) continuum of flux density
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
...and subject to dust reddening by a foreground screen (see more info on the extinction law) having a visual extinction of Av = mag (disabled) disabled


Instrument (CanariCam) and telescope configuration

Instrument optical properties:(more info)
Cryostat window:    
Filter: Focal plane mask:
Grating: Spectrum central wavelength: um
Detector properties:(more info)
Read noise of 3000 e- per pixel (and with 4x extra low frequency noise)
Dark current of 10^6 e-/s per pixel
Telescope configuration:(more info)
Mirror coating: aluminium 
Instrument port: disabled   up-looking (2 reflections)  side-looking (3 reflections)
Wavefront sensor for tip-tilt compensation: PWFS   (no OIWFS)


Observing condition constraints

Note: you should read the explanatory notes for the meaning of the percentiles and to ensure that your selected conditions are appropriate for the observing wavelength. Further details are available on the observing condition constraints pages.
Image quality: best 20%-ile 70%-ile 85%-ile any
Sky transparency (cloud cover): best 20%-ile 50%-ile 70%-ile disabled 90%-ile disabled 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: <1.2 1.5 2.0


Details of observation

Calculation method:(more info)
Select imaging, spectroscopy or polarimetry mode, and the calculation method objective (note: only first method is available for spectroscopy)
Imaging   Spectroscopy   Polarimetry 
  Total S/N ratio resulting from a total time of secs and with a fraction of exposures that observe the source (number of individual exposures will be calculated from frame time)
  Total integration time to achieve a S/N ratio of and with a fraction of exposures that observe the source
  Total integration time to achieve a Polarization Error of % with a fraction of exposures that observe the source
  Polarization Error (%) resulting from a total time of secs and with a fraction of exposures that observe the source
Analysis method: (more info)
Software aperture that gives 'optimum' S/N ratio and with a sky aperture times the target aperture
Software aperture of diameter (or slit length) arcsec and with a sky aperture times the target aperture
Output:
For spectroscopy, autoscale or specify limits for plotted spectra (lower wavelength um and upper wavelength um)


Last updated November 27, 2007 by Frank Varosi