Jupiter's great red spot doesn't appear to be in the correct position. Is there someway to reposition it?

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    Starry Night uses a file called "JupiterGRS.txt" located in the Sky Data folder to determine the mean longitude of the GRS. To change the GRS's position you can open this file and enter a new mean longitude. The GRS drifts non-algorithmically so the GRS mean longitude will need to be updated from time to time. The latest mean longitude is available from Sky & Telescope's excellent Great Red Spot web page.

     

    For Version 6: the File "JupiterGRS.txt" can be found in the SkyData folder.

    On Windows ---> the SkyData folder can be found in the Starry Night program folder.

    On Mac ---> the SkyData folder can be found by right clicking the Starry Night program and choosing "Show Package Contents" ---> Resources ---> SkyData

     

    For Version 7: the File "JupiterGRS.txt" can be found in the SkyData folder.

    On Windows ---> the SkyData folder can be found in (Windows) \Users\<YourUserName>\AppData\Local\Simulation Curriculum\Starry Night Prefs

    On Mac ---> the SkyData folder can be found in (OS X)  /Users/<YourUserName>/Library/Application Support/Simulation Curriculum/Starry Night Prefs

     

    For Version 8: the File "JupiterGRS.txt" can be found in the SkyData folder.

    On Windows ---> the SkyData folder can be found in (Windows) \Users\<YourUserName>\AppData\Local\Simulation Curriculum\Starry Night Prefs 8

    On Mac ---> the SkyData folder can be found in (OS X)  /Users/<YourUserName>/Library/Application Support/Simulation Curriculum/Starry Night Prefs 8

     

    When the file is opened it will say this:

     

    // Enter the mean longitude of the Great Red Spot on the following line. Visit // the Starry Night Pro website at http://www.starrynightpro.com to get the // latest value. 134.0

     

    The number in your file may be different.  It is the number that needs to be changed.

     

    Go to this webpage to find the current GRS number: http://www.skyandtelescope.com/observing/objects/planets/3304091.html?page=1&c=y

    Go to this webpage if the above link is broken: http://www.skyandtelescope.com/observing/transit-times-of-jupiters-great-red-spot/

     

    On the webpage above (approximately halfway down) it says:  "The predictions assume the Red Spot is at Jovian System II longitude 173°, based on historical trends noted by JUPOS."

     

    Given that the current prediction is 173° the number 134.0 found in our example file is in error and needs to be changed to 173.0.  So, change the file to say the following:

     

    // Enter the mean longitude of the Great Red Spot on the following line. Visit // the Starry Night Pro website at http://www.starrynightpro.com to get the // latest value. 173.0

     

    Save the file.  And, the GRS position will be corrected.  In the future, if the GRS is again out of position, repeat the process.

     

    Comments

    • Avatar
      JudyMike Feinstein

      This does not help me. Tell me where the data folder is and how to access the "JupiterGRS.txt" file...thanks

    • Avatar
      JudyMike Feinstein

      I've long since figured how to correct the JupiterGRS.txt but now I get predictions that are 24hrs early...that is exactly one day early. Easy to extrapolate but still disapointing...thanks....Mike