Re: Top ten brightest satellites

From: Dr. T.S. Kelso (
Date: Wed May 19 2010 - 22:06:03 UTC

  • Next message: Bob King: "Re: Top Ten brightest satellites"

    As you point out, the list on Chip's site is probably based on the list 
    on CelesTrak at (although 
    that list does not contain magnitude information). That list was created 
    at the request of Jay Respler, but I really haven't received any 
    suggested additions or deletions for some time.
    I am certainly willing to take inputs from anyone on this list as to how 
    to update that list. Just let me know if I can help.  - TS
    Dr. T.S. Kelso
    Ed Cannon wrote:
    > 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
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