It is very reasonable that you saw Iridium 921 (tum)(bling) - and that goes for my friend Bengt also, who saw it about four minutes before the ISS+STS pass at 16:56 UTC on Dec.15, just above Mars. Incidentally, Bengt was one of the first to report an Iridium flare, in August 1997, before the phenomenon was identified. I think I noted that an Iridium was close, but it was only late autumn-winter, when IridFlar was available, that I could verify the flare. It is very difficult to find a flashing rate for a tumbling Iridium, since it has at least eight good flat surfaces (3 MMA, three body sides, flat bottom, (parallell) solar panels). Unless the rotation is very fast, a flash will be much fainter the next time, because the satellite has moved several degrees, and the reflection is no longer specular. I have collected quite a few negative-magnitude flash observations from 921 (and other Iridiums) in the hope of determining a rotation axis, but because of the many surfaces, and (probably) a rapid precession of the axis, a large number of observations are needed in a short period (a month or so). If you wish to find notes about a possible pattern, search on SeeSat-L using Google, from page http://www.satobs.org/seesat/seesatindex.html (but my search gave no true hit - I'm sure that's wrong) > At 06:38 UT (give or take a minute either way) this morning as I let my dogs out > into the backyard I happened to glance towards Polaris and saw a mag -1.0 > Iridium type flare from an unknown. (55° Elev. 5° Azm.) > Using FindSat the nearest sats to this position were Cosmos 2322 and Iridium 921 > tum. As the flare was travelling towards the north and Cosmos 2322 would have > been travelling towards the SE, the obvious choice would be Iridium 921 tum. The > only other time I have seen 921 was on the 13/06/01 at 23:38 UT when I had a > nice -2.0 flare at (35° Elev. 95° Azm). > Does anybody have any information on this Sat i.e.:tumbling rate etc: to support > my conclusions.? > ----------------------------------------------------------------- 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
This archive was generated by hypermail 2b29 : Sun Dec 16 2001 - 07:12:40 EST