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Moonstick Co. Sunsetwheel

• Type: circular custom
• Size: 11 Inches / 28 cm
• Material: Plastic
• Scales:
  • Front: date / time / timezone and map window

Instructions on reverse. A perpetual sunrise and sunset calculator. Useful (with use of correction tables on reverse) in the period AD 1 through AD 4000. Depicted is a prediction of sunrise in Seattle, Washington, for 7 March 2005 at 6:34 am. The date disk includes a complicated array of red and blue marks against which you align the map window. The time of event disk, in the center, includes red and blue filters to filter out the marks to be disregarded from the lower disk. Really, it's a lot easier than it sounds.

Settings are a little tricky given the small scale of the map (and my high northern latitude). You think this thing is big at 11 inches (It doesn't fit in my scanner), but it could be a lot bigger.

Sunsetwheels are available from the inventor at http://www.moonstick.com/.