picPET -- Precision Event Timer http://www.leapsecond.com/pic/picpet.htm
On Wed, Oct 18, 2017 at 1:33 PM, Rob Seaman <sea...@noao.edu> wrote: > Attila Kinali wrote: > > On Wed, 18 Oct 2017 08:47:58 -0600 > > Rob Seaman <seaman at noao.edu <https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts>> wrote: > > > > > 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. > > > > What is this black box supposed to do? Just provide a PPS? IRIG-B? > > Or does it need to have time-stamping capabilities? If so, how many > > channels? > > > > What are your time precision/accuracy requirements? > > > > What how cheap is "cheap"? What is the volume? > > Thanks for the quick reply. I should have included the subject line in the > message: > > "inexpensive, black box, GPS or NTP based TTL time capture” > > Telescope domes are filled with equipment, in particular the camera > shutter, that can be instrumented to issue a pulse suitable for hardware > time capture. We use Meinberg IRIG PCIe cards to trap these and read the > timestamps using their library routines under Linux. “Black box” to the > person I was talking to meant no IRIG in the dome, no Linux, and no PCIe > slot, but rather a self-contained unit that syncs to GPS. When last he > implemented such a feature at another telescope he didn’t even have time > capture, but rather the device issued a trigger at a specified moment, so > the timestamp and the shutter opening were inverted. He also seems to > prefer the timestamps be issued on a serial connection, not via library. > > Unlike laboratory instrumentation, a telescope environment needs to be > both very automated and very forgiving. Money may also be constrained. > However, telescopes are also often very flexible and I am willing - no, > eager - to consider completely different arrangements of equipment. > > So, reliable timestamping of a TTL input is the ulitmate goal. One channel > would be sufficient, but multi-channel would not invalidate an option. PPS > or IRIG-B (DCLS IEEE-1344) are not required, but might form an intermediate > part of the solution. Reference could be GNSS or possibly NTP. > > Precision varies, but milliseconds down to microseconds. Accuracy should > match the precision, meaning UTC accurate to same. Extra credit for > multiple timescale support. > > Cheap is what I want to know. I see the previous thread on BB-black and > could imagine a solution using the real time capabilities of that for a few > hundred bucks, but these are not experimenters, per se. That’s why they > want a black box. Volume is one to several, but could imagine a bulk order > if savings were significant. Hundreds of dollars might be the price point. > > Thanks! > > Rob Seaman > University of Arizona > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
