KOOLS-IFU Exposure Time Calculator

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Input

Wavelength
grism
observing wavelength		[Å]
integral range (e.g., pixel, spectral resolution, etc.)		[Å]
Object Flux
Point source or Extended source with Gaussian profile
object magnitude		[AB mag]
object flux in the wavelength range		[erg cm-2 s-1] * Total flux in the "integral range"
seeing (or FWHM of target)
Extended source with uniform brightness
object magnitude		[AB mag arcsec-2]
object flux in the wavelength range		[erg cm-2 s-1 arcsec-2]
Number of combining fibers		1 fiber = 0.6111 [arcsec2]
Observation Settings
exposure time of a frame		[sec]
number of frames
Sky Condition
sky background brightness		[AB mag]
		[erg cm-2 s-1 arcsec-2 Å-1]
Airmass Elevation		1 / cos(90° - Elevation)
		[deg]
For Experts
field of view per fiber		[arcsec2]
optics throughput (including atmosphere and telescope)		[%] (cf. see throughput@20220722)
number of combining fibers
object flux fraction in aperture (Gaussian 3-sigma for point source)		[%]
Atmosphere Extinction (extinction curve)		[mag/airmass]
Extinction rate		[%] : Extinction * ( Airmass - 1 )
number of extract pixels for fiber direction		[pixel]
readout noise		[e- / pixel]
wavelength-pixel scale		[Å]
M1 radius		[cm]
M1 shaded radius by M2		[cm]

Result

total exp time (overhead included)	S/N	total signal [e-]	total noise [e-]	object photon noise [e-]	sky photon noise [e-]	readout noise [e-]
sec
min