RE: Measuring accuracy of camera time codes

From: Derek C Breit (
Date: Tue Jun 02 2009 - 22:58:27 UTC

  • Next message: Marco Langbroek: "Re: Measuring accuracy of camera time codes"

    How do you know that??? We know from occultation timing that what you say
    below is not true, though everyone thinks it is..
    It is somewhere around +/- 0.5s on average. Sometimes better, sometimes
    worse.... Worse yet is that it varies constantly, not including the
    variance, also constantly, of what the camera itself does.. Add in the fact
    that everyone will get a different result, and it's really fun.. Traffic on
    the Net and what your computer is doing at the time all have an effect..
    But *You* characterizing *your* camera can, and should, be done.. But a
    different computer with a different camera, even of the same model, will
    return different results..
    You can certainly pin down the second in which an "event" occurs and claim
    an accuracy of +/- 0.5s. But not much more..
    Proving it is the issue..
    I do have your little program saved on the desktop and will show how
    inaccurate it is as soon as I get a chance.. Maybe Saturday.. Maybe the
    following week..
    This is a well known issue and is why Occultationists developed GPS time
    inserters accurate to 1 msec using the 1PPS..
    I'll let you know what I come up with when I have some data..
    I have a typical ping time of 100ms round trip to the 
    Navy time source so my error is no worse than half that.
    - George Roberts
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