Hi Steve and List, > What is the highest elevation for a major iridium flare of -6 or better with > the sun at between 0 and -5 on the horizon? My latitude is +39 . I have > seen a couple of daytime flares, but a -8 with dark skies is incredible. At 39 degrees north, your highest elevation flare exceeding magnitude -6 can theoretically exceed 70 degrees elevation. However, these can only occur just before sunrise or just after sunset. You're better off with higher contrast -- i.e. darker skies at the expense of a few degrees of elevation. The inverse square law won't hurt the brightness much, if at all, since it can be compensated by the cosine projected area factor for the MMA. If you relax the elevation angle constraint to 50 degrees, there are a number of -6 or brighter flares that occur under much darker skies. These will always be descending node passes in the predawn hours for passes in late-June to early August (left MMA), and ascending passes in predawn hours for late November to mid-January (right MMA). -6 or brighter evening flares, when the flare elevation exceeds 50 degrees, occur from the very end of March to mid-April, and the first half of September (though early morning -6 flares are also possible in mid-September). These evening bright flares above 50-degree elevation are always descending node passes. Best, Rob ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Thu Aug 09 2001 - 16:23:49 PDT