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# ARCHIVE - Forecast relative to the night starting on 2019/06/25 MST

Note: click on a figure to magnify the image.
Date of figures refers to the start of night in MST.

# FLAO

FLAO is the Single Conjugated Adaptive Optics (SCAO) system of LBT. The wind speed at which the system is therefore sensible is the integral of the wind speed of all the turbulence layer developed on the whole atmosphere. Such a velocity is called ‘equivalent velocity’ (Veq – Eq.1), it is defined as an integral of the wind speed weighted by the CN2 and normalized by the turbulence developed on the whole atmosphere.
 $V_{eq} = \left[ \frac{\int_{H_{min}}^{H_{max}} |v(h)|^{5/3} C_N^2(h) dh}{\int_{H_{min}}^{H_{max}} C_N^2(h) dh} \right]^{3/5}$ (1)

The integral is considered between the primary mirror (Hmin=Hprim) and the top of the atmosphere i.e. around Hmax = 20 km. Fig.1 show the equivalent wind speed Veq temporal evolution between the sunset and the sunrise as indicated in Eq.1 during the night.
Astronomical dusk and dawn are shown too. On the x-axis is time in UT (bottom), in MST (top). Raw data points frequency is equal to the model time-step (typically from a fraction of second up to a few seconds depending on the model configuration used). Data points are re-sampled at a frequency of 20 minutes after a 1-hour moving average. The error bars are the sigma over the 20 minutes sampling, computed before the moving average. Veq gives us an information on how fast/slow an AO system has to run.

 Fig. 1: Veq temporal evolution between the sunset and the sunrise.