How important is time keeping on the TSI?
The TSI-880 supports automated synchronization of the time clock to an internet time services such as NIST’s atomic clock. On the TSI-440, time must be accurate to about one minute to keep the shadowband tracking properly. There are actually two clocks to worry about: one on the mirror that calculates the ephemeris, and a second on the PC that sets the image’s time stamp. The clock on the mirror control system is quite stable, and the width of the blocking strap makes it not such a big deal if the mirror time drifts a few minutes or so. If you check the clock every month or two on the TSI itself this is adequate. If your PC is networked to the internet, a task that can be automated is setting the clock on your PC via a shareware program available from http://www.nist.gov.
