The first one was Iridium 82, labelled with ? because it does not have the operational orbit, with nodal period 100.4 minutes. As a 'spare' in 'engineering orbit' (it is assumed?) it does not constantly need perfect attitude alignment, as the operational ones do. Therefore, HA do not predict them, but in our experience they are (almost) as reliable as the operational ones. Perhaps you were W of Winnipeg, so Ir80 was fainter then predicted, but lucky with the orientation of Ir82 so that it was as predicted by Rob Matson's IridFlar (below). You would have had a whole suite of flares from +0 to +4 aside from those you saw, which is usually the case with low flares. Ir# S Date Local Time Azm El RA Decl (km) N Ill Azm Elev M Angle Mag Mag Mag Latitude Longitude (km) ***** ******** *********** **** ******* 82 ? 2002- 5- 4 23:21:45.5 266 21 7h50 13.6 1572.7 A Lit 329 -17.9 F 0.21 -6.4 -6.7 -8.0 49.9257 -97.0292 15.8 E 39 2002- 5- 4 23:22:34.0 266 23 7h57 15.1 1609.3 A Lit 329 -18.0 F 2.30 1.8 -6.7 0.2 49.9856 -94.6139 189 E 80 2002- 5- 4 23:31:46.6 268 19 7h51 13.5 1769.3 A Lit 331 -18.7 F 0.24 -5.7 -6.5 -7.5 49.9243 -96.9368 22.4 E ----- Original Message ----- > I was out with my Intro astronomy group for a planetary observing session, > and we were watching for the predicted -6 mag. flare of Iridium 80 at 23:31 > local (for Winnipeg, Manitoba, Canada). 10 minutes *before* the predicted > flare, we observed a mag -6 flare in the right spot. We thought we had > written the prediction down incorrectly (we hadn't), but watched until the > predicted time anyway. At the predicted time there was a fainter, -2 flare > in about the right spot as well. What would have caused the first one? It > looked like an Iridium flare, but which one? Heaven's Above didn't predict it. ----------------------------------------------------------------- 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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