Astron is the first watch to automatically recognize all time zones on Earth. With the touch of a single button, Astron adjusts to the correct local time everywhere on the planet. Seiko Astron is accurate to one second every 100,000 years, thanks to the time signal it receives from the Atomic Clocks in each GPS satellite. Astron receives all the power it needs from light absorbed through the dial. Not just sunlight, it is able to use all kinds of light, and store excess energy it produces in a power reserve with charge level is indicated on the dial. Astron receives GPS signals even when the wearer is walking or in a vehicle. If you can see the sky, Astron will tell the exact local time, even as you move across borders. Astron has a perpetual calendar that will not need to be manually corrected until February 28, 2100.