RE: And I thought if Nanosail D was obseved flashing, means it's rotating

From: Ted Molczan (
Date: Sat May 28 2011 - 15:03:47 UTC

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    Thierry Legault wrote:
    > Ted, I fully agree with you about the importance of the rule.
    > Instead of making a long e-mail, I have made a page describing a deep
    > technical analysis of recent Nanosail images from Mr Vandebergh. As
    > you suspect, shape and colors are artifacts. I think that the new
    > rule is especially interesting in this "textbook case". I even think
    > that now a few raw images extracted from the video are not
    > sufficient, the full avi file would be very interesting to assess.
    > The analysis:
    Thank you for sharing your analysis. I will leave it to those skilled in the art and science to comment on your methods
    and conclusions, but I wish to point out that this is the sort of reasoned approach and presentation that I want to
    encourage here.
    I appreciate your support for the new rules (link below), but I continue to be open to suggestions for improvement,
    especially from those like you and Ralf who are active in the field. 
    I think the value of many of the requirements is obvious (e.g. fully identifying the observed subject, circumstances of
    the observation, equipment used), but I suspect that some of the more technical items, like #8 through #11 (see below),
    could be improved:
    8. Tracking method: hand-guided, or mechanical (make/model)
    9. Data acquired: total duration, frame rate, exposure per frame, resolution & bit depth of raw data
    10. Processing: describe the process of frame-selection and/or image-processing used to obtain reported results.
    11. Raw image frames: Results consisting of one or more frames selected from a longer series of frames, whether
    image-processed or not, must be supported by at least 60 seconds of the complete set of raw frames centred on the time
    of the results, i.e. 30 s before and after. By raw frames is meant the data exactly as taken from the camera that formed
    the input into the process of frame-selection and/or image-processing that produced the result. If the result is
    displayed on a web site, then a link to the raw data should be located in close proximity. An alternative would be to
    place a statement that the data is available upon request in close proximity to the results.
    Regarding #11, is 60 s too much, or too little? What if circumstances (weather, obstructions) sometimes result in less
    than 60 s of data, yet the observer believes that she obtained a useful result? The spirit of the rule is to provide
    sufficient context to evaluate the reasonableness of the result, so I suspect that I would accept quite a bit less in
    exceptional cases. On the other hand, I suspect that no matter where I set the rule, 60 s, 45 s, 30 s, there will be
    those who will argue for even less. Your thoughts?
    Also related to #11, would it be beneficial to offer an exemption in cases where no extraordinary claims of resolution
    are made? The intent would be to minimize the burden on those reporting results, especially beginners or casual
    participants. For example, a beginner or casual observer manages to image/video ISS, which clearly reveals its general
    shape, and for which he is not claiming to have resolved details that push the limits of what could be reasonably
    expected given aperture and range to target.
    First, is the raw frames requirement much of a burden, especially to a beginner? 
    If so, could a formula be derived, perhaps based on the one for diffraction limited resolution, that could serve as the
    threshold, such that only claimed/implied resolution of features smaller than that, would trigger the raw frames
    requirement? I want something that promotes good science, without being overly burdensome, or discouraging beginners,
    and also easy (for me) to administer. I would likely insist that the inevitable compromise be biased at least somewhat
    in favour of good science. After all, the laws of physics apply, regardless of whether we understand them or find it
    convenient to heed them.
    Ted Molczan
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