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: http://www.satobs.org/position/posn_formats.html http://www.satobs.org/tumble/flashpm.html 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, satobs.org _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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