RE: Greetings, and a short-lived mystery

From: Derek C Breit (
Date: Fri Jan 21 2011 - 01:27:33 UTC

  • Next message: Bill Arnold: "Obs for Jan. 20"

    Hello Mal...
    Look at the other Iridium 9XX's... They all show somewhat the same
    behavior... And if you have long horizon to horizon pass of, say Iridium
    911, they will flash / flare in three places, with the center set being at
    the same declination as the Sun, and the other sets roughly 45 degrees north
    and south of there..
    Give or take..
    Derek - Morgan Hill, CA
    -----Original Message-----
    [] On Behalf
    Of Mal Ninnes
    Sent: Thursday, January 20, 2011 3:29 PM
    Subject: Greetings, and a short-lived mystery
    Hi all,
    I've been following this list for the last 6 months or so after finding the
    satobs site during a late night web surfing session.   Imagine how surprised
    I was to learn that I wasn't the only person who likes watching spy
    satellites.  :-)  Anyhow it's good to be able to introduce myself after
    following some of the posts of the regulars over the last few months.
    Tonight I observed Lacrosse 5 (10:54 UTC - 11:05 UTC, Jan 20) on a NW-ENE-SE
    pass, the highest point being 84 degrees altitude.  I need a deck chair,
    because those overhead passes sure do strain the neck. I never want to look
    away, either, as that'll no doubt be the point when I miss a flash/flare.
    Anyhow, just after Lacrosse 5 passed through the zenith, a flash caught my
    eye to the NNW at about 30-40 degrees above the horizon. I quickly forgot
    Lacrosse 5 and focused on this new area, catching another flash and getting
    a basic idea of the track of this new satellite. I'd seen Iridium flares
    before, but this looked different (more than one flare).  It was travelling
    at the same speed as Lacrosse 5, but on a different orbital plane.
    I estimated the flashes to be 0.25-0.5 sec in duration, occurring every 4
    seconds. One flash was quite bright (probably at least mag -3) in comparison
    to the others (about 0-1).   First observed NNW at about 30-40 deg (11:00:00
    UTC), maximum altitude 60-70 degrees (11:02:00 UTC), then disappearing from
    the naked eye to the SSW at about 30 degrees altitude (approx 11:03:30 UTC).
    I ran inside, keen to figure out what this bird was.  I've stumbled across
    new satellites before, but after firing up heavens above and looking for
    satellite tracks to match, I came up empty.   I then resorted to some
    element sets that I'd loaded into heavensat, and found that Iridium 911
    seemed to fit the bill.  I couldn't explain the flashing.... until I looked
    up 24842 in heavens above, and found the note that it was tumbling.  Mystery
    solved.   I might have to add this sat to my list of ones to watch.   The
    constant flashing and somewhat unpredictable magnitude of the flashes was
    I also finally got to observe USA 215 for the first time on Fri 31 Dec 2010
    (after waiting several weeks), which was great.  It definitely won't be the
    last time I see it.  Finally, I'm also hoping to acquire some binoculars and
    possibly some new photo & video equipment soon (keen to see more than the mk
    1 eyeball can provide) to generate some more accurate observations.
    Anyhow, clear skies for NROL-49, and let's hope that Nanosail-D puts on a
    good show.
    Mal Ninnes
    Sydney, Australia
    -33.727 +150.919
    Seesat-l mailing list
    Seesat-l mailing list

    This archive was generated by hypermail 2b29 : Fri Jan 21 2011 - 01:28:19 UTC