Re: Obs 15-09-2009

From: Daniel Trads (danielts@post8.tele.dk)
Date: Wed Sep 16 2009 - 07:54:06 UTC

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    Hi
    
    Yes I noticed that Windows own time synchronization is only accurate to one second (sntp). We've had some issues at my work where we used it to synchronize a SCADA system, but after I used a real ntp client the problems disappeared. The servers are now synchronized within 10 ms. I use the same system at home. It's the win32 build of the official ntpd deamon. http://www.meinberg.de/english/info/ntp.htm
    
    Then the second problem is to read the stop time from the computer. If you double click on the clock in the taskbar you can see the current time. I've also noticed that the second part is changing rather unstable. I've started to use the clock shown in Heavensat which updates it's fields at least 10 times pr. second.
    
    I'll try to use my cam to make a frame-by-frame analysis to check if the above is correct.
    
    Marco Langbroek wrote:
    > Daniel Trads schreef:
    >> Using a cell phone as a stopwatch. Laptop synchronized using ntpd 
    >> 4.2.4p7. Heavensat 2.1.9. ObsReduce 1.3.
    > 
    > Daniel: did you use your laptop as a time reference?
    > 
    > Please be advised: that is not going to work! Even with internet time 
    > synchronization, the clock is not accurate enough. The indicated times 
    > are unstable and depend a.o. on what processes are running on the 
    > computer! They can be off considerably.
    > 
    > - Marco
    > 
    > -----
    > Dr Marco Langbroek  -  SatTrackCam Leiden, the Netherlands.
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