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Satellite hint plugin shows very strange data

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Anonymous
2012-12-06
2015-03-12

  • Anonymous
    2012-12-06

    Last night I donwloaded and and installed stellarium on win XP. I turned on satellite hint plugin and I noticed OPS 8180 (RADCAT) satellite on very strange orbit. It was further than a moon (about 450000 km). It was also very fast about one degree per second. I did some research on the internet and I 've found that it's orbit was very different:
    http://nssdc.gsfc.nasa.gov/nmc/spacecraftOrbit.do?id=1972-076A
    Furthermore it is decayed:
    http://www.n2yo.com/satellite/?s=6212

    I tried to look on celestrak page (where supposedly data for stellarium comes from) but I couldn't find anything useful there.

    Below is the data form stellarium of tonights projected position of this satellite:

    OPS 8180 (RADCAT)
    Catalog #: 06212; International Designator: 1972-076A

    RA/DE (J2000): 4h58m41.2s/-10°03'11.3"
    RA/DE (of date): 4h59m18s/-10°02'03"
    Hour angle/DE: 19h17m2s/-10°02'03" (geometric)
    Hour angle/DE: 19h17m28s/-9°53'49" (apparent)
    Az/Alt: +111°11'10"/+4°27'08" (geometric)
    Az/Alt: +111°11'10"/+4°37'34" (apparent)

    Range (km): 523237.96
    Range rate (km/s): -0.276
    Altitude (km): 517419.73
    SubPoint (Lat./Long.): -9.35°/90.901°

    TEME coordinates (km): X: 140020.30, Y: 497509.30, Z: -85102.42
    TEME velocity (km/s): X: 0.09, Y: -0.17, Z: -0.85
    The satellite is visible.

     

  • Anonymous
    2013-02-05

    I have just noticed the same thing.

     

  • Anonymous
    2013-02-07

    Yes, me too.

     
  • barrykgerdes
    barrykgerdes
    2013-02-07

    This is a common problem with OPS 8180.

    This satellite crashed last september and is still in the satellite list because the update does not remove old satellites. It only updates the ones it has update info on.

    Remove the old satellites.json file in you user area and let the update generate a new one.

    The most likely cause is that the TLE gives a decaying orbit that now probably revolves around the centre of the earth in a few minutes.

    Barry

     
    • waldo kitty
      waldo kitty
      2013-02-08

      On 2/7/2013 17:26, barrykgerdes wrote:

      This is a common problem with OPS 8180.

      This satellite crashed last september and is still in the satellite list because
      the update does not remove old satellites. It only updates the ones it has
      update info on.

      i sure hope this gets handled soonest...

      Remove the old satellites.json file in you user area and let the update generate
      a new one.

      because this is very painful when importing 12000 satellite TLEs and then also
      selecting them all to enable their "show orbit" options...

      The most likely cause is that the TLE gives a decaying orbit that now probably
      revolves around the centre of the earth in a few minutes.

      i've seen this a few times :LOL: it takes some luck to click on the satellite or
      stop the time advance and then walk it manually to catch the satellite to see
      which one it is so it can be removed... the really fun ones are those that you
      remove which get added right back on the next update because they are still
      valid and flying but the orbit code doesn't calculate properly for them...

       

    • Anonymous
      2013-10-06

      no you are not right!
      i noticed a very fast light in the sky last days,.

       

  • Anonymous
    2013-06-07

    I do not understand this. I saw exacltly like all of You, but I saw it at the sky. It was strange to me, but when I turned on Stellarium, it was pointing thaht OPS 8180 was there at that time (UTC +1, Belgrade, direction NW). I do not undesrtand how I saw some light flashing over time last night. I do not thinck that it was ariplane.

    I do not using Stellarium to track satellites, but it was so strange to me.

     
  • barrykgerdes
    barrykgerdes
    2013-06-07

    If you have not removed OPS8180 from your data base by deleting the old satellites.json file the chances of it showing on your screen at any given instant are about 2:1. What you saw in the sky at that time could have been anything but certainly not OPS8180 which no longer exists.

    As for deleting the old json file every time it updates is exactly the problem that was stated by Waldo kit. There can be thousands of satellites to add which will take some time. By just updating only those necessary we can avoid this. To make sure that you don't have old satellites in the file you need to manually delete the old file and generate a new one every couple of weeks.

    Barry

     
    • waldo kitty
      waldo kitty
      2013-06-08

      On 6/7/2013 18:35, barrykgerdes wrote:

      As for deleting the old json file every time it updates is exactly the problem
      that was stated by Waldo kit. There can be thousands of satellites to add which
      will take some time. By just updating only those necessary we can avoid this. To
      make sure that you don't have old satellites in the file you need to manually
      delete the old file and generate a new one every couple of weeks.

      agreed but that is not optimal... every other program that tracks satellites
      works from the raw TLE files every time... they may generate a file for the
      birds they choose to watch but if those birds are not listed in the current TLE
      file(s) being used, they are not shown at all...

      ideally stellarium will move away from the current XML format and importation
      and work directly from the TLE files... this would do several things...

      1. save the long and tedious step of conversion to XML...
      2. save on the file size since the XML is much larger than the TLE files
        directly...
      3. save on processing time needed to read the TLEs and convert them to XML...
      4. eliminate the need to delete old satellites...
      5. eliminate the need to delete the entire XML file and start over...

      those five items, at least, will go a long way to helping the satellite tracking
      capabilities of stellarium...

      since the TLS files have to be read anyway, just skip the XML completely and
      we're half way there... without the need of the XML file, we reach the end of
      the other half and we're more golden than we are now ;)

      --
      NOTE: No off-list assistance is given without prior approval.
      Please keep mailing list traffic on the list unless
      private contact is specifically requested and granted.

       
  • Bogdan Marinov
    Bogdan Marinov
    2013-06-08

    It's not XML, it's JSON.

    Anyway, the next version of the Satellites plug-in (pending merge) will address issues like this one - it has an option to automatically remove satellites that are not listed in the update files, and an option to automatically add new satellites from selected update sources. The "auto-import" option combined with the offline update option (from local files) can work effectively as a mass TLE import from files.

    Any satellites imported during the last session are put in the "newly added" pseudogroup, so you'll be able to select them all and set whatever settings you want for the orbit. In the new version, the execution time of mass operations on the display and orbit flags should be greatly improved. (Before, it looked up linearly each selected entry, effectively making the execution time quadratic... An example of poorly executed code reuse.)

     
    Last edit: Bogdan Marinov 2013-06-08
    • waldo kitty
      waldo kitty
      2013-06-08

      On 6/8/2013 07:53, Bogdan Marinov wrote:

      It's not XML, it's JSON.

      sorry... but the end result is the same... conversion of a simple TLE format
      into something much larger and more convoluted...

      i can understand wanting something to keep descriptions and radio frequencies in
      but the TLE data really should not be stored in any files other than their
      original TLE files... as mentioned before, it saves a lot of hassle but i will
      definitely be giving the new version a good testing when i get hold of it ;) O:)

      Anyway, the next version of the Satellites plug-in (pending merge) will address
      issues like this one - it has an option to automatically remove satellites that
      are not listed in the update files,

      that should help with the current problem of satellites no longer flying...

      and an option to automatically add new satellites from selected update sources.

      that will be nice, too...

      The "auto-import" option combined with the offline update option (from local
      files) can work effectively as a mass TLE import from files.

      i think i'm following this but will have to see it in operation... as it is, i
      currently run 3 or 4 satellite trackers besides stellarium... the biggest PITA i
      deal with is each wants to use its own copy of the TLE files and i see no need
      in downloading them 3 or 4 times and wasting all that drive space... i'd rather
      that each program use the same TLE files and check the file's dates to see how
      old they are before downloading new ones... then leave the downloaded ones in
      place for the others to use... in this way, i can start with any of the ones i
      use and the TLEs will be updated for all... i would just need to make sure that
      each is set for the same "days old" setting... in my case, that's always "1 day
      old" ;)

      Any satellites imported during the last session are put in the "newly added"
      pseudogroup, so you'll be able to select them all and set whatever settings you
      want for the orbit. In the new version, the execution time of mass operations on
      the display and orbit flags should be improved.

      it would be nice to have a place where we can set what options to always be set
      on the newly added satellites... i do not always remember to go select them all
      and turn on display orbit...

      also, i've asked once or twice before (without response) about the followup on
      the orbit calculations we talked about a while back... the ones where satellites
      were showing up with bad orbit calculations which made them fly by real fast...
      i have screenshots of one that is real high up and takes only seconds to
      traverse the wide area of visible sky... you had said that you would try to get
      hold of the person who wrote that code and see about a fix... what was the
      result of that? has there been a fix to that orbit calculation code to handle
      that problem? it kinda sucks to have to delete a satellite that is still flying
      but is not having its orbit calculated correctly...

      as always, thanks for your time and all your work on stellarium as well as this
      small part of the project... it is greatly appreciated ;)

      --
      NOTE: No off-list assistance is given without prior approval.
      Please keep mailing list traffic on the list unless
      private contact is specifically requested and granted.

       

  • Anonymous
    2013-06-09

    TLE sounds good imo , how about going further and have a configurable dedicated Sat tracker plugin that monitors warns/beeps for upcoming passes and all that stuff?
    Developers please keep at it as your doing a wonderful piece of artwork here :-) , I'm embarrassed that I cannot help out , money OR programming ....

     

  • Anonymous
    2013-08-07

    I had the same problem too. That's weird....
    I don't really mind it. I can just ignore it if it already fell to the Earth.

     


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