Simultaneous Iridium flares

From: Robert Holdsworth (
Date: Tue Mar 25 2003 - 05:19:33 EST

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    This evening 25 March at 20:15 local (UTC plus 12) I observed with the naked
    eye simultaneous Iridium flares from a location at Wellington waterfront
    (41.2861 S; 174.779 E at 0 degrees elevation.)
    These were from Iridium 28 1997-051-E  and Iridium 94 2002-005-C
    Although I did not have an accurate means of timekeeping, the  flare times
    according to Heavens Above were 20:18:38 for I.94 and 20:18:39 for I.28
    respectively.  To the naked eye they appeared to brighten and diminish at
    exactly the same time.
    Azimuth of both was 174 degrees-  predicted magnitude of I.94 was -7 as
    against -3 for I.28, and respective altitudes were predicted as 25 degrees
    and 22 degrees.  Ground tracks were very similar.
    I was only 2.6 km from the flare centre for Iridium 94, as against 17.8 km
    for Iridium 28.  I did notice that the higher flare was brighter, though I
    would not have said it was such a marked difference in magnitude as that
    predicted.  The sky was clear but being very close to  the central city area
    there was considerable background light though it caused little difficulty
    with the observation.
    I would be interested to know how rare or otherwise sightings of
    simultaneous flares are.
    (Flares were predicted here at 20:31 and 20:32 on 23 March local from
    Iridium 33 and 91 respectively but unfortunately I was not able to attempt
    an observation at that time.)
    Robert Holdsworth
    New Zealand
    41.26100S, 174.94700E
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