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Wavefront coherence time - τ0

Wavefront Coherence Time (τ0) Maps Temporal Evolution

Forecast relative to the night starting on 2026/06/15 MST

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

Wavefront coherence time horizontal map extended on a 50km x 50km square surface centred on LBT (represented with a black dot). The Wavefront coherence time is integrated over three different vertical slabs:

TOTAL WAVEFRONT COHERENCE TIME (τ0,TOT) – [dome-20000]m
BOUNDARY LAYER WAVEFRONT COHERENCE TIME (τ0,BL) – [dome-600]m
FREE ATMOSPHERE WAVEFRONT COHERENCE TIME (τ0,FA) – [600-20000]m

The wavefront coherence time in each pixel is obtained integrating the CN2 and wind speed along the zenith and covering the temporal range [dusk,dawn]. The animations show the temporal evolution with 1-hour steps (in UT and MST). The black iso-lines represent the heights of the Digital Elevation Model (DEM).

Fig. 1: τ0 map [50×50]km integrated on [20-20000]m
Time animation with 1-hour steps

Fig. 2: τ0 map [50×50]km integrated on [20-600]m
Time animation with 1-hour steps

Fig. 3: τ0 map [50×50]km integrated on [600-20000]m
Time animation with 1-hour steps

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Horizontal maps average

Wavefront coherence time - τ0

Wavefront Coherence Time (τ0) Maps Averages

Forecast relative to the night starting on 2026/06/15 MST

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

Wavefront coherence time horizontal map extended on a 50km x 50km square centred on LBT (represented with a black dot). The seeing is integrated over three different vertical slabs:

TOTAL WAVEFRONT COHERENCE TIME (τ0,TOT) – [dome-20000]m
BOUNDARY LAYER WAVEFRONT COHERENCE TIME (τ0,BL) – [dome-600]m
FREE ATMOSPHERE WAVEFRONT COHERENCE TIME (τ0,FA) – [600-20000]m

The wavefront coherence time in each pixel is obtained integrating the CN2 and wind speed along the zenith and covering the temporal range [dusk,dawn]. The black iso-lines represent the heights of the Digital Elevation Model (DEM).

τ0,TOT AVERAGES:

Averages are computed over the whole night [<dusk> – <dawn>] UT and also in the first, central and last part of the night (see partition).

Fig. 1: τ0,TOT over the whole night [<dusk> – <dawn>]UT time frame

Fig. 2: τ0,TOT over the “first part of the night”.

Fig. 3: τ0,TOT over the “central part of the night”.

Fig. 4: τ0,TOT over the “last part of the night”.

τ0,BL NIGHT AVERAGES:

Averages are computed over the whole night [<dusk> – <dawn>] UT and also in the first, central and last part of the night (see partition).

Fig. 5: τ0,BL over the whole night [<dusk> – <dawn>]UT time frame

Fig. 6:τ0,BL over the “first part of the night”.

Fig. 7: τ0,BL over the “central part of the night”.

Fig. 8: τ0,BL over the “last part of the night”.

τ0,FA AVERAGES:

Averages are computed over the whole night [<dusk> – <dawn>] UT and also in the first, central and last part of the night (see partition).

Fig. 9: τ0,FA over the whole night [<dusk> – <dawn>]UT time frame

Fig. 10: τ0,FA over the “first part of the night”.

Fig. 11: τ0,FA over the “central part of the night”.

Fig. 12: τ0,FA over the “last part of the night”.

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Wavefront Coherence Temporal evolution nn

Wavefront coherence time - τ0

Wavefront Coherence Time (τ₀) Temporal Evolution

Forecast relative to the night starting on 2026/06/15 MST

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

Temporal evolution of the wavefront coherence time integrated in different vertical slabs between the sunset and the sunrise:

TOTAL WAVEFRONT COHERENCE TIME (τ0,TOT) – [dome-20000]m
BOUNDARY LAYER WAVEFRONT COHERENCE TIME (τ0,BL) – [dome-600]m
FREE ATMOSPHERE WAVEFRONT COHERENCE TIME (τ0,FA) – [600-20000]m

Astronomical dusk and dawn are shown too.
On the x-axis is time in UT (bottom), in MST (top). Mountain Standard Time MST=UT-7. Data points frequency is 2 minutes. 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.

Fig. 1: Temporal evolution of τ0,TOT ([dome-20km]) between the sunset and the sunrise.

Fig. 2: Temporal evolution of τ0,BL ([dome-600m]) between the sunset and the sunrise.

Fig. 3: Temporal evolution of τ0,FA ([600m-20km]) between the sunset and the sunrise.

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