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NACO Exposure Time Calculator

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

Template Spectrum: Spectral Type : (only JHK)
Blackbody : Temperature : K

Target Magnitude : =

Magnitudes are given per square arcsec for extended sources.

Spatial Distribution: Point Source Extended Source

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

Neutral Density Filter: Out       In
Wollaston Prism System: Out       In
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%)
V,R,I,J,H [0.45 - 1.8] microns
(90%)
J,H observations
with WF sensing in K
FREE The NAOS-PS will try to find an optimal Dicroic/WFS combination. Note
Filter:
Camera:
Instrument mode:

Results

Aperture radius:  ×λ/D = arcsec

The two dynamic input fields are mutually updated when one of the values changes. The value in the "arcsec" field is updated if the filter is changed. The upper limit of the aperture radius is half of the camera FOV.
To revert to the default aperture for the current filter, press here:


S/N ratio: S/N = DIT = s Please note the relevant minimum DIT in the NACO manual.
Exposure Time: Non-chopping: NDIT =
Chopping : Total Exposure Time = minutes

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

2-D PSF image (jpg and FITS ) (point source only)
Encircled Energy as a function of Aperture Radius (point source only)
S/N as a function of Exposure Time
      

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