Re: Re: flashing period of 2005-04 B object 28538

Date: Wed May 02 2012 - 17:41:39 UTC

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    Thanks for your answer.
    Following your advice, I decided to make another determination of the period without taking in account the camera times at all.
    I used those times given by Calsky along its computed track in the finder chart.
    I detemined an accurate location for both maxima in the Calsky field of stars and read the times given by Calsky.
    On 21 Apr 2012, both observed maxima were distant from 57.2 +- 0.2 sec what gives a period of 11.44 sec +- 0.04 sec , instead of the 11.43 sec+- 0.10 sec formerly derived using the camera time. The first rough determination took less than 2 minutes and saved about a half an hour job. LOL
    Best wishes
    Message du : 29/04/2012 16:46
    De : "Björn Gimle " <>
    A :
    Copie à :
    Sujet : Re: flashing period of 2005-04 B object 28538
    I meant to answer you on your previous post of the similar nature, but
    didn't have time to work through an example (and still don't before
    May 13 ?).
    If you can determine the true time to 1s from your camera time, or
    have faith in the accuracy of the elset, or verify it against current
    observations, you can determine the track speed very accurately with
    Ted's ObsReduce. A few seconds error (or more) changes the track very
    Using the times you can estimate, and the pixel coordinate method of
    Obsreduce, it will detemine the corrections from the elset to your
    points, so you can compute when it "ought to be" at those positions.
    This should allow you to determine the times as accurately as the
    image permits, and even compute flash intervals spanning several
    > ...
    > Although each maximum can be located quite accurately on the satellite's track registered on the photos, the period accuracy is limited by the fact the time of each photo is given at the second only by the clock of my Canon EOS 600D camera. It would need to know the time of each photo at the tenth of second.
    Björn Gimle, COSPAR 5919
    59.2576 N, 18.6172 E, 23 m
    Phone: +46 (0)8 571 43 312
    Mobile: +46 (0) 704 385 486
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