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 (mcnames.zip) from this page: http://www.io.com/~mmccants/tles/index.html 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 qsmag.zip on this page: http://www.io.com/~mmccants/programs/index.html 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 http://mailman.satobs.org/mailman/listinfo/seesat-l
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