RE: Accurate Timings

From: Matson, Robert (
Date: Fri Jun 02 2000 - 16:14:08 PDT

  • Next message: Patrick: "ISS Magnitude"

    Hi Patrick,
    > I've been trying to make accurate timings of satellites for a while, and I
    > can't figure out how you guys do it.  The closest I can get is about two
    > three seconds, because I have to look down at my stopwatch and then back
    > at the satellite, which takes some time.  So my question is, what's your
    > strategy?
    Sounds like you may need a more capable stopwatch.  The ones
    that we use for satellite flash timings, etc., store multiple
    "lap times" -- some as many as 100.  This is essential for
    flash timings or logging multiple position points during
    a pass.
    However, if you only need to time one event (e.g. the
    conjunction of a satellite with a bright star), then my
    advice is to start your stopwatch a few minutes prior to
    the expected event, synchronized with an accurate watch
    on the minute.  For example, let's say that your satellite
    is supposed to nearly occult Vega at 9:33:17pm.  Looking
    at your watch, start your stopwatch when the time is
    exactly 9:30:00.  Then wait for your satellite.  At the
    moment of closest approach to Vega, hit the stop button.
    Whatever the stopwatch time reads, add that to 9:30:00
    to get the exact time of the conjunction.  With this
    technique, you should never have to look at your stopwatch
    while the satellite is flying over.  --Rob
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    This archive was generated by hypermail 2b29 : Fri Jun 02 2000 - 16:11:55 PDT