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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 LIRIS, please use IAC's LIRIS S:N calculator.

Instrument Instrument:
Detector:
Grating:
Band: Bandwidth:
Slit width, or fibre or lenslet diameter (arcsec):
Exposure time (sec):
Object Object:
Apparent magnitude: (/arcsec2 if extended)
(to enter Jy, add a minus sign)
Sky 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)
Output
format
Format:
Graph: S/N vs from to
Multiple curves
Parameter: 
Values: Curve 1 Curve 2 Curve 3


 
Optional
retrieving
/ saving of
parameters
input to
SIGNAL

Name of previously-saved parameter set.

Name for saved parameter set (if left blank, name is generated automatically).

Comments to accompany saved parameters:


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).

For an estimate of the additional time required for observing overheads and for calibration exposures, consult the ING's total observing time estimator.

This is version 14.5 of SIGNAL. Last Updated: 6 May 2014.

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



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Contact:  (WHT Manager)
Last modified: 19 July 2022