Admin: policy for reporting high resolution ground-based imagery of Earth satellites

From: Ted Molczan (
Date: Wed Aug 11 2010 - 12:06:26 UTC

  • Next message: David Tiller: "RE: Admin: policy for reporting high resolution ground-based imagery of Earth satellites"

    I am seeking the guidance of SeeSat-L subscribers to help develop a policy regarding the reporting
    of high resolution ground-based imagery of Earth satellites.
    In recent years, this activity has become feasible for amateurs, and a few SeeSat-L subscribers have
    reported their results. The Shuttle and ISS are the most popular subjects. Their large size and low
    altitude puts them well within the grasp of even modest amateur equipment. Results vary
    considerably, but resolution generally is sufficient to at least identify the objects by their
    distinctive shape; the best images reveal much more, and can be aesthetically appealing.
    There are many other interesting objects besides the Shuttle and ISS, but virtually all are much
    more distant and/or smaller. A few amateurs who relish the technical challenge posed by such
    objects, have begun to report their results. I am among those who have long hoped for this
    development, because it offers the prospect of finally learning the appearance of spacecraft like
    KeyHole and Lacrosse; however, it is my impression that this aspect of the hobby remains early in
    its development stage. I say this with all due respect to the imagers, who have taken on the great
    challenge of extracting useful detail from images of objects subtending as little as a few arc
    seconds, despite comparable astronomical seeing.
    The results I have seen to-date typically have seemed too low in resolution to reveal much, if any,
    useful information. If I stare at some images long enough, I may begin to see hints of overall shape
    and even finer detail, but with insufficient confidence to draw conclusions. Repeatable results,
    from more than one observer, would go a long way toward building confidence. That is something
    positional and rotational observers regularly achieve, but those fields have matured over decades.
    Until now, my policy has been to say little, and wait for the state of the art to improve; however,
    as moderator of SeeSat-L, which is an amateur science forum, I cannot ignore the controversy that
    has arisen here and in other forums, where it has been suggested that some observers may be
    over-processing their imagery, or overly influenced in their selection of individual video frames by
    the known/hypothesized appearance of objects. I believe that we should take these concerns
    seriously. Although we are amateurs, on SeeSat-L we try to promote good science, and do reasonable
    work within our limitations. 
    During the first four decades of the space age, several members contributed many thousands of
    precise positional observations of satellites, that were used by professional scientists for
    geophysical research into Earth's gravitational field and upper atmosphere. More recently, the
    mystery of the Iridium flares was discovered through observations reported to SeeSat-L, and solved
    by SeeSat-L members, who developed the algorithms now used to routinely predict flares. We also
    observe and maintain accurate orbits of nearly 300 objects in secret orbits, and our findings are
    valued by professional researchers and journalists. So we know the value of good science, and wish
    to see amateur high resolution ground-based imagery of Earth satellites mature to the point where it
    can contribute to public knowledge.
    I see a couple of broad policy options for SeeSat-L:
    1. We could decide that high resolution ground-based imaging is sufficiently different from the
    mainstream of visual observing, that routine observations would best be presented and discussed in a
    specialized forum. Those interested in both aspects of visual observing could join both forums.
    SeeSat-L members could still learn of exceptional results via links to reports and articles posted
    to our list, and added to our web site.
    2. In keeping with our "big tent" policy, we could continue to encourage posting of routine results,
    but in accordance with reporting guidelines that promote good science, at a level appropriate to
    amateurs, similar in concept to those that apply to positional and rotational observations. Lengthy
    discussion or debate would be discouraged, in keeping with long-standing policy that SeeSat-L is a
    low-volume list, mainly to facilitate and share observations, and relevant news.
    I lean toward option 2, but I want to hear from list members.
    In case of option 2, we would need to develop appropriate reporting standards. Amateur satellite
    observers long ago developed reporting standards for positional and rotational observations, which
    are required on SeeSat-L:
    The concept is to provide sufficient information for someone skilled in the art and science to
    evaluate and make use of the data. 
    Given the complexity involved, I imagine high resolution imaging could benefit from some or all of
    the following:
    ID of object: COSPAR, USSTRATCOM catalogue number, common name
    Description and dimensions of object (metres), if known.
    Observing site: lat, long, alt, to nearest 100 m
    Date/time of obs: UTC
    Range to object: km
    Telescope: make/model/aperture
    Camera: make/model
    Data acquired: total duration, frame rate, exposure per frame, resolution & bit depth of raw data
    Tracking method: hand-guided, or mechanical (make/model)
    Processing: detailed description of processing used to obtain reported results.
    Raw image frames: when the claimed or implied resolution strains the limits imposed by distance of
    subject, aperture of telescope, and typical atmospheric turbulence, final processed results should
    be accompanied by the complete set of raw data from which they were derived. For example, if the
    result is displayed on a web site, then a link to the raw data would be located in close proximity.
    An alternative would be to state that the data is available upon request.
    I am interested in your comments and suggestions; I would especially look to imagers for guidance as
    to what is appropriate.
    Ted Molczan
    Admin, SeeSat-L,
    Seesat-l mailing list

    This archive was generated by hypermail 2b29 : Wed Aug 11 2010 - 12:09:01 UTC