> I'm interested in automatically measuring the earth's period by looking > close to straight up with a fixed telescope.
Here's a related idea for you; a modern digital sundial. Two different ways to implement it: 1) Aim a webcam on a standard sundial and write some image processing software that at the pixel level monitors the amount of shadow in real-time compared to PC time (UTC). By the end of a day, you'd have enough samples to have nailed down solar time quite accurately. Collecting data over weeks or months would be even more revealing. Fun math and programming problem. 2) Instead of a fixed base, gnomon, and slowly moving shadow like almost all sundials, you put a stepper or servo motor/encoder on the base. Then place matched photodiodes on either side of the gnomon and steer the whole sundial for constant *minimum* shadow. In real-time, a PC or microcontroller monitors the photodiodes, keeps the sundial in position, and logs continuous position data (as a function of UTC). At the end of the day your precise measure of solar time drops out of this data. At night it extrapolates where it should aim the sundial for sunrise. Again, collecting days or weeks of data gives you even greater precision. 2b) Do the same using a PC-controlled telescope, where software constantly adjusts Az-El to maximize the measured brightness of the filtered sun through the eyepiece/CCD. /tvb http://www.LeapSecond.com _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
