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NACO Exposure Time Calculator

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Infrared Adaptive Optics Spectroscopy Mode Version 6.0.0
Description.
F.A.Q
 
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Target Input Flux Distribution

Template Spectrum: Spectral Type (only JHK) Target Magnitude:
= Vega AB
Magnitudes are given per arcsec2 for extended sources.
MARCS Stellar Model:
Blackbody Temperature : K
Single Line
Lambda: nm
Flux: 10-16 ergs/s/cm2 (per arcsec2 for extended sources)
FWHM: nm

Spatial Distribution: Point Source Extended Source (per pixel)

Adaptive Optics Mode:

LGSLaser Guide Star
NGS

Natural Guide Star

Target / Reference Source
Separation: arcsec
Reference Source
V mag: Spectral Type

Sky Conditions

Airmass:
Seeing: arcsec FWHM in V-band at zenith (use this value in the proposal). The seeing is irrelevant for extended sources.
Probability 60% for a seeing smaller or equal to the requested value
A model of the AO-corrected PSF is used to define the S/N reference area. See the helpfile for details.

Instrument Setup

NAOS WFS/Dichroic:
Dichroic Name Reflected light to the WFS
(Efficiency)
Transmitted light to CONICA
(Efficiency)
Conditions of use
VIS V,R,I [0.45 - 0.95] microns
(90%)
J,H,K,L,M [1.05 - 5.0] microns
(90%)
Near-IR observations
with optical WF sensing
N20C80 V,R,I,J,K [0.45 - 2.55] microns
(20%)
V,R,I,J,H,K [1.05 - 5.0] microns
(80%)
WF sensing and
observing in the IR
N90C10 V,R,I,J,K [0.45 - 2.55] microns
(90%)
V,R,I,J,H,K [1.05 - 5.0] microns
(10%)
WF sensing and
observing in the IR
JHK I,J,H,K [0.8 - 2.55] microns
(90%)
L,M [2.8 - 5.5] microns
(90%)
Thermal-IR observations
with WF sensing in the near-IR
K K [1.9 - 2.55] microns
(90%)
J,H [0.45 - 1.8] microns
(90%)
V,R,I,J,H observations
with WF sensing in K
FREE The NAOS-PS will try to find an optimal Dicroic/WFS combination. Note
Slit:
Grism/Filter Mode:
Instrument mode : (select Double_RdRstRd for LW).

Results

S/N ratio: S/N = DIT = sec Please note the relevant minimum DIT in the manual.
Exposure Time: NDIT =

The total exposure time is the product of DIT (Detector Integration Time) by NDIT (number of DITs). Instrument and telescope overheads are not taken into account.


Plots: Toggle All / No Plots

Resultant spectrum including sky
Object Spectrum only
Sky Emission Spectrum
Sky Transmission Spectrum
S/N as a function of wavelength
Total Efficiency and Wavelength Range
Input spectrum in physical units
Point Spread Function (point source only)
Enslitted Energy (point source only)

Detailed S/N info
      

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