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Loading contentA layer showing which part of the sky is above the horizon for an observer at a given place and time. Computed from the observer's location and the clock — no observing conditions are assumed or invented, and location stays on the device.
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.