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#1
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unidentified satellites
OK guys - here's another question. I use Heavens-Above regularly
and their listing(s) seem quite comprehensive. There are often several satellites per hour listed for my viewing area on any given night. They list down to visible mag. 4.5. Tonight between scheduled satellites, I viewed two that were not listed by Heavens-Above and they were relatively bright, easily mag. 4.0 or more. My question is this: Is there a particular reason why these satellites are not listed by them. Is it an oversight? Is the data not available to them? Are these "secret" therefor "unlisted" satellites? Anyone have an explanation for this. Also, is there possible a site that has more listings that may include these unidentified satellites? Thanks in advance for any suggestions. Tony P.S. This morning I allowed myself an hour and a half viewing window from 0315 to 0445 PDT and tracked 8 satellites, the 2 unidentified mentioned above plus these 6: Spot 1, Lacrosse 3, Cosmos 1975, Cosmos 1340, Lacrosse 4, and Cosmos 1980. |
#2
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unidentified satellites
"Tony Vinci" wrote in message
om... OK guys - here's another question. I use Heavens-Above regularly and their listing(s) seem quite comprehensive. There are often several satellites per hour listed for my viewing area on any given night. They list down to visible mag. 4.5. Tonight between scheduled satellites, I viewed two that were not listed by Heavens-Above and they were relatively bright, easily mag. 4.0 or more. My question is this: Is there a particular reason why these satellites are not listed by them. Is it an oversight? Is the data not available to them? To the best of my knowledge, Heavens-Above bases its magnitude estimates on standard magnitude data produced by hobbyists. The hobbyist data is of two types. For hundreds of objects, it has been derived from many thousands of precise positional and magnitude observations. Here are a few examples from the SeeSat-L archive: http://satobs.org/seesat/Dec-1995/0029.html (UARS) http://satobs.org/seesat/Dec-1995/0043.html (KeyHole) http://satobs.org/seesat/Dec-1995/0093.html (Vostok upper stages) http://satobs.org/seesat/Dec-1995/0101.html (Tselina-2 satellites) For many other objects, the standard magnitude has been estimated based on their published dimensions, or in some cases their published Radar Cross Section. Our standard magnitudes are accurate, but they are mean values, with variances of 1 magnitude or more quite common. The variances are the unavoidable consequence of our inability to know the precise surface characteristics and orientation of most satellites. (The Iridiums are one of few exceptions.) Practically, this means that an object predicted to be magnitude 5.0, could reach magnitude 4 or brighter, but would be omitted from Heavens-Above's mag 4.5 predicted list. In a few cases, Heavens-Above does appears not to have up to date magnitude data. For example, Japan's first spy satellites, 03009A (std mv = 5.7) and 03009B (std mv = 3.2) often are quite bright, but Heavens-Above does not yet have their magnitude data. Several pieces of operational debris from that launch also are bright, including some good flashers. No doubt, in time the data for these objects will be added. Also, is there possible a site that has more listings that may include these unidentified satellites? Heavens-Above mentions an All Visible Passes option for registered users, with the ability to set your own magnitude cut-off. Perhaps that would be worth a try. Ted Molczan |
#3
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unidentified satellites
"Tony Vinci" wrote in message
om... OK guys - here's another question. I use Heavens-Above regularly and their listing(s) seem quite comprehensive. There are often several satellites per hour listed for my viewing area on any given night. They list down to visible mag. 4.5. Tonight between scheduled satellites, I viewed two that were not listed by Heavens-Above and they were relatively bright, easily mag. 4.0 or more. My question is this: Is there a particular reason why these satellites are not listed by them. Is it an oversight? Is the data not available to them? To the best of my knowledge, Heavens-Above bases its magnitude estimates on standard magnitude data produced by hobbyists. The hobbyist data is of two types. For hundreds of objects, it has been derived from many thousands of precise positional and magnitude observations. Here are a few examples from the SeeSat-L archive: http://satobs.org/seesat/Dec-1995/0029.html (UARS) http://satobs.org/seesat/Dec-1995/0043.html (KeyHole) http://satobs.org/seesat/Dec-1995/0093.html (Vostok upper stages) http://satobs.org/seesat/Dec-1995/0101.html (Tselina-2 satellites) For many other objects, the standard magnitude has been estimated based on their published dimensions, or in some cases their published Radar Cross Section. Our standard magnitudes are accurate, but they are mean values, with variances of 1 magnitude or more quite common. The variances are the unavoidable consequence of our inability to know the precise surface characteristics and orientation of most satellites. (The Iridiums are one of few exceptions.) Practically, this means that an object predicted to be magnitude 5.0, could reach magnitude 4 or brighter, but would be omitted from Heavens-Above's mag 4.5 predicted list. In a few cases, Heavens-Above does appears not to have up to date magnitude data. For example, Japan's first spy satellites, 03009A (std mv = 5.7) and 03009B (std mv = 3.2) often are quite bright, but Heavens-Above does not yet have their magnitude data. Several pieces of operational debris from that launch also are bright, including some good flashers. No doubt, in time the data for these objects will be added. Also, is there possible a site that has more listings that may include these unidentified satellites? Heavens-Above mentions an All Visible Passes option for registered users, with the ability to set your own magnitude cut-off. Perhaps that would be worth a try. Ted Molczan |
#4
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unidentified satellites
Hello Tony,
There are predictionprograms you can run yourself with the satelements you want. Go to the seesat-l homepage at: www.satobs.org/satintro.html here you find links to several programs and places to get satelements. Also to Rob Matsons Skymap, which you can use to ID observed UNIDs Greetings Leo Barhorst "Tony Vinci" schreef in bericht om... OK guys - here's another question. I use Heavens-Above regularly and their listing(s) seem quite comprehensive. There are often several satellites per hour listed for my viewing area on any given night. They list down to visible mag. 4.5. Tonight between scheduled satellites, I viewed two that were not listed by Heavens-Above and they were relatively bright, easily mag. 4.0 or more. My question is this: Is there a particular reason why these satellites are not listed by them. Is it an oversight? Is the data not available to them? Are these "secret" therefor "unlisted" satellites? Anyone have an explanation for this. Also, is there possible a site that has more listings that may include these unidentified satellites? Thanks in advance for any suggestions. Tony P.S. This morning I allowed myself an hour and a half viewing window from 0315 to 0445 PDT and tracked 8 satellites, the 2 unidentified mentioned above plus these 6: Spot 1, Lacrosse 3, Cosmos 1975, Cosmos 1340, Lacrosse 4, and Cosmos 1980. |
#5
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unidentified satellites
Hello Tony,
There are predictionprograms you can run yourself with the satelements you want. Go to the seesat-l homepage at: www.satobs.org/satintro.html here you find links to several programs and places to get satelements. Also to Rob Matsons Skymap, which you can use to ID observed UNIDs Greetings Leo Barhorst "Tony Vinci" schreef in bericht om... OK guys - here's another question. I use Heavens-Above regularly and their listing(s) seem quite comprehensive. There are often several satellites per hour listed for my viewing area on any given night. They list down to visible mag. 4.5. Tonight between scheduled satellites, I viewed two that were not listed by Heavens-Above and they were relatively bright, easily mag. 4.0 or more. My question is this: Is there a particular reason why these satellites are not listed by them. Is it an oversight? Is the data not available to them? Are these "secret" therefor "unlisted" satellites? Anyone have an explanation for this. Also, is there possible a site that has more listings that may include these unidentified satellites? Thanks in advance for any suggestions. Tony P.S. This morning I allowed myself an hour and a half viewing window from 0315 to 0445 PDT and tracked 8 satellites, the 2 unidentified mentioned above plus these 6: Spot 1, Lacrosse 3, Cosmos 1975, Cosmos 1340, Lacrosse 4, and Cosmos 1980. |
#6
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unidentified satellites
Also, is there possible a site that has more listings
that may include these unidentified satellites? Here are some other sites with online predictions that might include other objects: http://web2.cnam.fr/vms/equipe/bmabboux/track.html http://www.calsky.com/ http://www.donbarry.org/sat/ Ed Cannon - - Austin, Texas, USA (Remove "donotspam".) |
#7
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unidentified satellites
Also, is there possible a site that has more listings
that may include these unidentified satellites? Here are some other sites with online predictions that might include other objects: http://web2.cnam.fr/vms/equipe/bmabboux/track.html http://www.calsky.com/ http://www.donbarry.org/sat/ Ed Cannon - - Austin, Texas, USA (Remove "donotspam".) |
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