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Loading contentHow large an object of known size appears at a given distance. The Moon and the Sun span almost exactly the same half-degree from Earth — the coincidence that makes total solar eclipses possible.
Formula: θ = 2 arctan(D / 2d)
With the default inputs, angular diameter evaluates to 1864.5 arcsec — The Moon → ~1865″ (0.52°). The validator recomputes this against the known value on every build, so the formula is checked, not asserted.
Facts on this topic will be cited from these primary and reference sources.
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.