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Does anyone know if there has been any work in determining the impact of the moon on sky brightness based on phase, moon altitude (including below the horizon), location altitude, humidity, etc? This has applications to astrophotography when deciding whether to image a target that is currently X° away from the moon at a certain phase. There is a classic approximated 'moon avoidance' formula which can be parameterized by target-moon separation angle and moon phase to account for wavelength - e.g. narrowband vs wideband filters. But the result doesn't differ whether the moon is above or below the horizon. Thanks -

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    $\begingroup$ Providing a link to the 'classic' rule-of-thumb formula you referenced would probably improve this question. $\endgroup$
    – antlersoft
    Commented Dec 19, 2023 at 13:52
  • $\begingroup$ Horizons provides various information related to this. ssd.jpl.nasa.gov/horizons/manual.html#obsquan $\endgroup$
    – PM 2Ring
    Commented Dec 19, 2023 at 17:32
  • $\begingroup$ If there is one, it's probably fairly involved as the atmospheric conditions will have a lot of impact. $\endgroup$ Commented Dec 19, 2023 at 19:25

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I don't think an accurate formula is possible. There's always some haze, but how much, and how it scatters light, varies. That's one of the reasons we go to space to get the best photometry.

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The ESO skycalc tool makes a calculation of sky brightness that incorporates many physical effects, including moonlight, starlight, zodiacal dust etc. You can get broadband magnitudes for different target-moon separations and for the moon at different phases and altitudes. It takes no account of local meteorological conditions and assumes the observer is at the Paranal site.

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