Re: About APCC and ISS tracking and PC Time

Dale Ghent

On May 25, 2021, at 05:31, Bob <astro@...> wrote:

Thanks Ray. Although, APCC could still use the GPS time without updating the computer time perhaps, which would get around the admin issue? I guess this could be problematic for other software though. I guess I will go with some third party software then.
The same clock discipline considerations that exist when syncing time to the PC clock would also exist when syncing to the mount. The PC clock and mount's own clock should also be in sync for reasons including proper precession calculations anyway, so it's best for the mount to be programmed with the PC's time, and the PC's clock to in turn be properly synchronized with a time source.

Time sources and synchronization on the PC is going to be far more flexible and readily doable in a correct way anyhow. NTP infrastructure takes care of these details in whole, with time sources being other NTP servers on the internet to local NTP infrastructure that's uses local time sources, such as a GPS receiver, rubidium clocks, or even NIST's WWV and WWVH shortwave radio. Absent NTP but with a GPS receiver on Windows, you can use NMEATime2. As far as the GPS function in APCC goes, it's useful for your lat/long. Time is going to be a more advanced concern.

As an aside, here's a little neat thing about time sync services, at least here in the US: The US Naval Observatory and NIST still operate telephone lines for their time services. You can call them at any time to hear an audible 1 PPS tick with time announcements every minute. It's pretty moot in the age of mobile phones that have clocks that are synced to the telephone switch's own atomic clock, but If anyone feels like hearing the voices of broadcasters Fred Covington (USNO) or John Doyle (WWV) crooning out the time at 2am, one can still do so.

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