Computing Exposure Times with the IRAF Package SPECTIME

Online help for SPECTIME

KP-4m/R-C Spectrograph

Set the integration time to INDEF or leave blank if you wish to compute the total exposure time needed to achieve the desired signal-to-noise per pixel at the central 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 [Å]:
Maximum time per single
exposure (seconds):

If the above wavelength is set to INDEF or blank it is computed from the blaze peak of the disperser. If the order is set to INDEF or blank the value is determined from the nearest order to the wavelength above.
Grating: Order:
Filter(1): Filter(2):
Slit width in arcsecs (+) or pixels (-): Slit length in arcsecs (+) or pixels (-):
Detector binning (dispersion): Detector binning (spatial):
Seeing (arcsecs): Airmass:
Lunar Phase (0-14 days from new moon, 0 = new, 14 = full):   

Describe the source with the following parameters. The power law index is only used if the source spectrum is set to F_power or F_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 wavelength of the source flux is ignored for source units = U, B, V, R, I.
Source spectrum:    Temperature (K) for blackbody source:    Power law index:
Wavelength () of source flux or magnitude:    Source flux or magnitude:    Units of source flux or magnitude:
E(B-V) (reddening of source in magnitudes):

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