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Exposure Time Calculator for Phoenix at KP-4m


Online help for the IRAF SPECTIME package

Set the integration time to INDEF or leave it blank if you wish to compute the total exposure time needed to achieve the desired signal-to-noise per pixel at the wavelength specified below. If you set the integration time to some value a new signal-to-noise per pixel will be computed for that time, ignoring what is in the signal-to-noise ratio box.

Integration time in seconds:      Signal-to-noise ratio:      At wavelength (µm):
Maximum time per single
exposure (seconds):


Slit width in arcsecs (+) or pixels (-):   Seeing (arcsecs):
Slit length in arcsecs (+) or pixels (-): 

Describe the source with the following parameters. The power law index is only used if the source spectrum is set to Flambda_power or Fnu_power. Setting the power law index to 0 is equivalent to a flat spectrum for that particular power law function. If the value of the wavelength of the source flux is set to INDEF then the central wavelength value above is used. The entry for the wavelength of the source flux is ignored for broadband source fluxes.

Source spectrum:    Temperature (K) for blackbody source:    Power law index:

Wavelength (µm) of source flux or magnitude:    Source flux or magnitude:    Units of source flux or magnitude:

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Last updated March 16 2012

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