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A figure of eight on a dial.
Also known as: Analemma marking, Time correction curve
The marking correcting apparent solar time to mean time, drawn as a long looped figure.
Gives the correction between apparent solar time and mean clock time through the year.
Contexts: History, Navigation
Its figure-of-eight shape comes from combining two independent effects — the tilt of the axis and the eccentricity of the orbit — so the curve is the sum of two cycles of different period and the lobes are unequal for that reason.
Contexts: History, Navigation
Makes a sundial usable as a clock: with the correction applied, apparent time becomes mean time and the dial agrees with a watch.
Contexts: History, Navigation
A narrow figure-of-eight curve engraved on a dial or a globe, its two lobes unequal, with dates marked along it.
The correction curve converts the dial's apparent time into mean clock time.