Re: Top ten brightest satellites

From: Ed Cannon (
Date: Wed May 19 2010 - 21:49:52 UTC

  • Next message: Dr. T.S. Kelso: "Re: Top ten brightest satellites"

    Bob King wrote:
    "I'm writing about the easiest satellites to see 
    with the naked eye and would like the list's help 
    on what you think are the brightest 10 or so out 
    there after the space shuttle and space station. 
    These satellites should be in high inclinations 
    so they're visible most places around the world."
    Well, first, I suggest including Iridium flares,
    since they are near-polar inclination and 
    predictable and just about the brightest 
    satellite phenomena of all.  (However, if they 
    are not flaring, Iridium payloads are faint.)
    Beyond that, if you mean just payloads and not 
    spent launch vehicles, etc., for sure four of 
    the brightest payloads (after ISS and HST) are 
    the (classified) Lacrosses:
    21147, 91-017A - Lacrosse 2 
    25017, 97-064A - Lacrosse 3
    26473, 00-047A - Lacrosse 4
    28646, 05-016A - Lacrosse 5
    Lacrosse 5 sometimes does a disappearing act on 
    a pass.
    The three big (classified) Keyhole payloads are 
    sometimes very bright (but often faint).  
    24680, 96-072A - USA 129
    26934, 01-044A - USA 161
    28888, 05-042A - USA 186
    In fact, many payloads in sun-synchronous orbits
    can be very bright at times, but you just have 
    to be lucky or figure out how to predict when 
    they will be bright.  Envisat is one of these.
    In our summer here at latitude 30 north, in the
    evenings there are quite a few sun-synch objects 
    that will flare very brightly in the vicinity of 
    the Big Dipper, or at least in the northwest.
    A couple of objects that are very interesting 
    because when they are brightest they sparkle 
    are USA 32 and USA 81.  When they do this, they 
    are fantastic when observed with magnification.
    >From latitude 30 north at least, they generally
    do their naked-eye sparkling relatively near 
    to the highest point in a pass (culmination).
    19460, 88-078A - USA 32
    21949, 92-023A - USA 81
    If you run predictions from day to day, there 
    are from time to time objects that will go over
    at low height and range and so are quite bright
    on those passes (given a good phase angle).  
    The Russians have a very large low-height 
    object in orbit from time to time that is under
    200 miles.  I can't recall what they are called,
    but usually they are in orbit for only four 
    months or so.
    Now, if you include spent launch vehicles, then 
    most Zenit vehicles (Russian, SL-16) and many 
    Long Marches (Chinese, Chang Zheng or CZ or LM) 
    are quite bright as long as you don't have bad 
    luck.  (Bad luck is when they are pointing at 
    you, so that you don't get a good reflection.)
    The oldest easily visible object is 00694, 
    63-047A, Atlas Centaur 2, but it's in a 
    low-inclination orbit and also due to tumbling
    slowly is very faint about half the time.  It's
    in an eccentric orbit and so can be seen at 
    times from higher latitudes, but of course 
    isn't as bright then since it's farther away.  
    That's also true of the Milstar 3 Centaur 
    (25724, 99-023A) which after 11 years is still 
    tumbling every couple of seconds or so.
    Sometimes the OAO 1, 2, and 3 launch vehicles,
    which I believe are Atlas Centaurs, do very 
    bright passes (but sometimes very faint, so 
    that I wonder if they are tumbling very slowly).
    The list that Ralph referenced used to be 
    maintained, by Jay Respler I believe, but as
    Russell pointed out is now out-of-date due to
    not including any recent objects.  (This is 
    somewhat like my list of flashing geosynchs, 
    which I have failed to update for a few years.)
    Rainer Kracht used to maintain a list of 
    40 to 50 brightest objects, but that's another
    list that we don't have anymore.
    If you go to Mike McCants' website and get 
    his MCNAMES file ( from this page:
    then you can, using Excel or something like
    that, manipulate the file so as to sort it 
    on the fourth column of numbers, which is 
    the intrinsic magnitude.  The brightest ones
    are magnitude 3.5 or brighter.  ("V" means
    visually observed and "d" means theoretically
    derived magnitude.)  Of course you need to 
    know their orbits also, for your purposes.  
    Centaurs are intrinsically bright but are 
    10th magnitude in geosynch orbits!  So you
    want only ones in low orbits.  You can use
    his Quicksat magnitude file in the same way.
    It's on this page:
    It at least identifies geosynchs and eccentric
    orbit objects with "g" and "h" flags, so that
    you can exclude those.  (And the "d" flag is
    for ones no longer in orbit.)
    Hope that helps some.
    Ed Cannon - Austin, Texas, USA
    Seesat-l mailing list

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