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CRIRES Exposure Time Calculator


Legacy version P95-phase2 (December 2014)
Provided for reference only!

This is not the normal ETC version www.eso.org/observing/etc

Infrared Adaptive Optics Spectroscopy Mode Version 5.0.1
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Target Input Flux Distribution

Uniform (constant with wavelength) Target Magnitude and Mag.System:   
= Vega
Spectral Type (Pickles Model): (only U-K bands)
MARCS Stellar Model:
Blackbody : Temperature : K
Single Line :
Lambda: The emission line is centered on the (doppler-shifted, if applied) requested wavelength specified below.
Flux: 10-16 ergs/s/cm2 (per arcsec2 for extended sources)
FWHM: nm

Spatial Distribution: Point Source Extended Source

Target Doppler Shift

No Doppler Shift
Target coordinates (J2000) and radial velocity
Coordinates (J2000) alpha:  hr min sec
delta:   deg min sec
Radial velocity
(relative to the barycenter of the Solar System)
km/s (Note: The velocity is negative for an approaching target)
Date of observation:       This information is used with the target coordinates to compute the doppler shift due to the orbital and rotational movement of the Earth (barycentric correction).
Time of observation UT:

Sky Conditions

PWV: mm   Precipitable Water Vapor.
Airmass: X= (X ≥ 1)
Seeing FWHM in V-band:
Seeing(at X)= arcsec [0.6-1.4] for NGS AO mode. Use this seeing in the phase I proposal and the OB constraints.
Seeing(at Zenith)= arcsec.
The seeing is assumed to scale with the airmass X like this: Seeing(X) = Seeing(Zenith) * X3/5.
The values in the two Seeing fields are mutually updated when one of the values changes. The field "Seeing(at Zenith)" also depends dynamically on the airmass value. To force an update of the dynamic fields, press here: . To revert the three fields to the default values, press here: .

Instrument Setup

Slit width: arcsec 
Reference Wavelength:
Standard Setting: (the full plot range and λreqref are automatically assigned)
Free Setting: λref= nm (and λreqref)
Requested Wavelength
λreq: nm.
The numeric results will refer to this wavelength (doppler-shifted, if applied).
In single-line mode, the emission line will be centered on this wavelength (doppler-shifted, if applied).
Wavelength range to plot:
λmin: nm
λmax: nm
The values in these fields are automatically updated to the full range when a Standard Setting changes. For a Free Setting, the λmin and λmax values are set to the corresponding full range by pressing the "set plot range" button.
The Reference Wavelength λref refers to the center (pixel 512) of detector3. Note: Wavelengths are in vacuum.
Detector mode: The detector RON depends on this mode and the DIT chosen below.

Adaptive Optics Mode:

noAO AO not enabled

Natural Guide Star

Target / Reference Source
Separation: arcsec. [0-30]
Reference Source (Vega magnitudes)
R mag: [0.0-16.3] B-R color (and equiv.spectral type)


S/N ratio: S/N = DIT = s
DIT range for detector modes:
[1.0s - 900s] FowlerNsamp, DIT ≥ 2s is recommended
[0.1s - 900s] FowlerNsampGrStWin
Exposure Time: NDIT =

The total exposure time is the product of DIT (Detector Integration Time) by NDIT (number of DITs). This exposure time does not take into account instrument and telescope overheads.

On submission the model can generate the following graphs:
(input parameters are replicated in the output page)

Plots: Toggle All / No Plots

Resultant spectrum including sky
Object Spectrum only
Sky Emission Spectrum
Sky Radiance Spectrum in physical units (ph/s/m2/micron/arcsec2)
Sky Transmission Spectrum
S/N as a function of wavelength
System Efficiency and Wavelength Range
Input spectrum in physical units
Target PSF and Slitwidth (point source only)
Enslitted Energy for the Target (point source only)
N2O Gas Cell Transmission Spectrum
Detailed S/N info


Legacy version P95-phase2 (December 2014)
Provided for reference only!

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