SIGNAL calculates the number of object and sky photons which will
be detected during an imaging or spectroscopic
exposure of a point or extended source
with one of the common-user instruments
of the Isaac Newton Group of Telescopes.
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Instrument
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Instrument:
Detector:
Grating:
Band:
Bandwidth:
Slit width, or fibre or lenslet diameter (arcsec):
Exposure time (sec):
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Object
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Object:
Apparent magnitude:
(/arcsec2 if extended)
(to enter Jy, add a minus sign)
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Sky
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Seeing (FWHM in arcsec):
Airmass:
Extinction(mag/airmass):
Sky brightness:
(mag/arcsec2)
(D, G or B for typical dark, grey or bright; or 0 for darkest sky on La Palma)
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If bandwidth, extinction and sky brightness are left set
at zero,
SIGNAL assumes sensible defaults (click on parameter name for details). A UBVRI sky-brightness calculator is available.
For details of the assumptions made by SIGNAL, or to access the code,
please see the
SIGNAL help page, or click on a parameter name above (NB the help page may open in a separate tab).
This is version 14.5 of SIGNAL. Last Updated: 6 May 2014.
