Phillip Clark wrote: >Quite a few years ago Nick Johnson had a paper published Perhaps it might be important to know about how many years ago. >So, unless the system has improved, the RCS values are very nice to look at >but useless in reality ! Since Jay got the RCS values included in the SSR, we now have nearly ten years experience with those values. Some values are clearly quite wrong. Some special values seem to mean "unknown value" or "default system value" and should be ignored. Values for objects that are usually higher than 10000 miles are often much too small or much too large. Taking the median (not the mean) of the last 50 or 60 values seems to produce a median value which is fairly well correlated with the observed visual magnitude, but of course the optical reflection properties (flashes and large changes in brightnes) cannot be expected to always compare to what amounts to an "average" radar reflection value. And, of course, some objects are white, some are black, and some are polished, so the RCS only provided a "guideline" as to what optical brightness might be expected. If an object explodes into many pieces, a visual observer would be wise to look for the ones with a larger RCS before looking for the ones with a smaller RCS. :-) Summary: I have been including the median RCS value in my printed visual predictions for many years and I compare my observed magnitudes with that median RCS value and I have not found all that many "discrepancies" in over 2500 different LEO objects in the last decade. Mike McCants ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www.satellite.eu.org/seesat/seesatindex.html
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