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Exposure Time Calculator – SIGNAL

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.

For NAOMI/OASIS and LIRIS, please use Lyon's OASIS S:N calculator, and IAC's LIRIS S:N calculator respectively.

Instrument setup Instrument:
Detector:
Grating:
Band: Bandwidth:
Slit width, or fibre or lenslet diameter (arcsec):
Exposure time (sec):
Object information Object:
Apparent magnitude: (/arcsec2 if extended)
Sky conditions Seeing (FWHM in arcsec):
Airmass: Extinction(mag/airmass):
Sky brightness: (mag/arcsec2) (D, G or B for typical dark, grey or bright)
Output options Format:
Graph: S/N vs from to
Multiple Curves curve 1: curve 2: curve 3:


This form lists only the currently available ING instruments and detectors, see separate page for other telescope/instrument options.

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 14.3 of SIGNAL. Last Updated: 21 Jan 2010.

© Isaac Newton Group of Telescopes
Developed by Chris Benn and Robert Greimel



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Exp. Time Calculator