Bram Dorreman wrote: >Most transits of GRACE Satellites result in steady appearing satellites. >Sometimes the conditions are suitable to let the two spacecraft show >one flare. I did not analyse those special cases. But I presume that >there might be a connection: GRACE's azimuth equals Sun's azimuth. I >did not prove this yet. >When one speaks about variable satellites, what does one mean? >Therefore my question: how many brightness variations were actually seen? Looking at the pictures they sent me it looks like there were two peaks in brightness (with different strength) of the leading satellite in the first picture and the trailing satellite shows up strongly on the first picture and much weaker at the second picture but at different positions than the leading one. The visual report mentioned the trailing satellite as being distinctly brighter than the first one which disappeared much sooner. So on that particular pass (19:02 UTC, 16-OCT-06) there seems to have been a difference in attitude between the pair. Today I observed a pass of the GRACE pair from my place (49.88N, 8.66E) when they appeared low in the western sky at 18:47/ 18:48 UTC (29-OCT-06). Almost due West they appeared bright at about mag 2 at identical positions before slowly fading. As the ideal flare surface would have been oriented less than 5 deg away from the nadir this was probably caused by the flat underside (which I think they have). So they definitely looked absolutely regular and perfectly controlled tonight. Gerhard HOLTKAMP Darmstadt, Germany ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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