[time-nuts] inexpensive, black box, GPS or NTP based TTL time capture?

Rob Seaman seaman at noao.edu
Wed Oct 18 10:47:58 EDT 2017


I’ve been working for the Catalina Sky Survey for a couple of years. For many years, CSS has been one of the most productive discoverers of Near Earth Objects (NEOs), that is, of asteroids and comets that are potentially hazardous to the Earth.

As you might imagine there are numerous interesting aspects to this project, and timekeeping is one. We use Meinberg clocks and IRIG PCIe cards to capture TTL signals from the stepper motor controller of the large camera shutters to attach accurate and reasonably precise UTC time tags to each celestial search field. Our telescope control also depends on knowing the time. Etc.

I’m at the annual planetary sciences meeting (in Provo this year) and several groups have expressed interest in duplicating our setup (details of FO converters, Schmitt triggers, etc, omitted) in a “cheap black box” to quote one fellow. Lots of people contribute productively to NEO observations, including amateurs and small teams with little funding. Improving their timekeeping would help keep rocks from falling on you and your family.

Any suggestions for a minimally expensive, maximally performing such arrangement? Or alternative architectures? One group has used:

	http://www.spectruminstruments.net/TM4.pdf <http://www.spectruminstruments.net/TM4.pdf>


Many thanks!

Rob Seaman
University of Arizona

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