Crescent Neptune and Triton

The Voyager 2 spacecraft camera captured the gas giant planet Neptune and its cloudy moon Triton together in crescent phase.

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The elegant picture of was taken from behind just after closest approach, in 1989. It could not have been taken from Earth because Neptune never shows a crescent phase to sunward Earth. The unusual vantage point also robs Neptune of its familiar blue hue, as sunlight seen from here is scattered forward, and so is reddened like the setting Sun.

source APOD