Assuming the viewer is far from any light pollution, it is a cloudless night, and humidity is very low. What is the faintest apparent magnitude of stars visible to the naked eye during a full moon (at zenith) if the viewer is looking towards the horizon?

  • 2
    $\begingroup$ Shouldn't you be asking about the faintest stars that are visible, rather than the brightest? $\endgroup$
    – D. Halsey
    Sep 26, 2019 at 0:47
  • 1
    $\begingroup$ Yup! Thank you. $\endgroup$
    – Bob516
    Sep 26, 2019 at 0:52
  • $\begingroup$ So what you're really asking, I think, is what's the faintest visible star visible on the horizon at midnight (sun opposed) when the moon is not in the field of view. A nice clean, dry, cold atmosphere means there's almost no scatter from the moon's output into your FOV. $\endgroup$ Sep 26, 2019 at 14:42
  • $\begingroup$ Would there be no scatter of the moon's output reaching the FOV I'm asking about? I didn't know whether there would be or not. $\endgroup$
    – Bob516
    Sep 26, 2019 at 16:08
  • $\begingroup$ Related question $\endgroup$
    – Mike G
    Sep 26, 2019 at 16:52

1 Answer 1


Wikipedia's page on the Bortle Scale claims the full moon at a dark site is roughly equivalent to the light pollution at the urban/suburban transition which means you could see stars with an naked-eye limiting magnitude (NELM) 4.6-5.0


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