X-SHOOTER Exposure Time Calculator

X-SHOOTER Echelle Spectroscopy Mode Version P113
Description
FAQ
 
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Target Input Flux Distribution

Template Spectrum Redshift
z =
Target Magnitude and Mag.System:   
= Vega
AB
Magnitudes are given per arcsec2 for extended sources
MARCS Stellar Model
Upload Spectrum
Blackbody Temperature: K
Power Law Index:           F(λ) ∝ λindex
Emission Line
Lambda: nm
Flux: 10-16 ergs/s/cm2 (per arcsec2 for extended sources)
FWHM: nm



Spatial Distribution:
Point Source    Extended Source

Sky Conditions

Moon FLI: Airmass:
Almanac
Time
Time step forward/back



Target
Target coordinates Name or ID:  
α      δ     
UT rise
culm.
set
Hour Angle azimuth altitude zenith distance airmass FLI moon/sun
phase angle
moon/target
separation
Target
Moon
Sun
An advanced almanac is available in the ESO SkyCalc sky model calculator
PWV:     mm     Probability % of realising the PWV ≤ 10.00 mm
Seeing/Image Quality:
Turbulence Category:   (FWHM of the atmospheric PSF outside the telescope at zenith at 500 nm)
IQ: arcsec FWHM at λ= nm (of long-exposure of stellar images at airmass of observations)
Image Quality is not a parameter in AO modes
              The corresponding seeing and turbulence category will be indicated in the output page
Image Quality is not a parameter in AO modes
The output will always include the IQ at λ=600nm and the IQ at the central λ of each arm


Instrument Setup

Arm selection, Exposure Times and Detector modes:
Arm
Slit Width
Exp.Time
NDIT

NEXP or NINT

Detector Mode
(gain) (spatial×spectral binning) (readmode)
UVB:
Texp: s
 
NEXP:
VIS:
Texp:s
 
NEXP:
NIR:
DIT:s
NDIT:
NINT:
 

Note! The current version of the ETC includes the 0.6" and 0.9" NIR slits without the K band blocking filter. For the preliminary performances of the new 0.6" and 0.9" slits with the K band blocking filter please refer to the X-shooter User Manual.

In UVB and VIS, the total exposure time T is the product of Texp (Exposure Time) and NEXP (Number of EXPosures): T = Texp × NEXP.

In NIR, the total exposure time T is the product of DIT (Detector Integration Time), NDIT (Number of DITs) and NINT (Number of INTegrations): T = DIT × NDIT × NINT.

Note! Stray-light contribution in the NIR arm is not accounted for. This effect is increased for wide slits (increased background) and faint, K>14 targets (higher percentage of total flux due to stray light), and could result in a factor 3-5 higher noise than predicted.


Results

Include exposure times for S/N: (currently not enabled for NIR)
Tables:  Toggle All / No Tables
Spectral Format
Expected Counts
       
Graphs:  Toggle All / No Graphs
Input Spectrum
Efficiency
Obj
Sky
Maximum Intensity
S/N