Sky quality

Sky quality parameters

  • Sky extinction effect close to the horizon with TNG and GTC telescopes at the forefront.
    Atmospheric extinction

    Atmospheric extinction is the astronomical parameter that evaluates sky transparency. Besides the natural extinction due to the molecules of the atmosphere, other sources of sky transparency

  • Evolution of the turbulence profile for the night of 26th May 2006 at the ORM.
    CN2 turbulent vertical distribution

    The parameters relevant for Adaptive Optics can be obtained from the optical turbulence profile, given by the refractive-index structure constant of the turbulence, C N 2 (h), where h is the altitude.

  • Top mast of an automatic weather station.
    Meteorology and climate

    Wind speed and direction, wind gust, relative humidity, air temperature, rainfall, insolation, etc.

  • Night Sky Background
    Night Sky Background

    The sky brightness (SB) is the routine measurement of the night sky brightness in units of magnitudes per arcsecond2 in a moonless night. This allows for identifying possible contaminating sources

  • Eagle Nebula in IR and Visible (credit Hubble Space Telescope). The PWV impacts the IR sky quality.
    Precipitable Water Vapour

    The principal molecule responsible for the absorption in IR is water vapour (WV). The total amount of WV above a particular location is highly variable and commonly expressed as the Precipitable Water

  • Outline of the DIMMA seeing monitor at OT with the Moon
    Seeing and coherence time

    Astronomical seeing (units arcesec) refers to the blurring or instantaneous image broadening of astronomical objects caused by turbulent mixing in the Earth's atmosphere due to the variations of the