Adding images

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Anonymous
2014-02-22
2014-10-30

  • Anonymous
    2014-02-22

    I've browsed back several pages but haven't found anything, so...

    I would like to add some of my own images of deep sky objects. But when i open the ngc2000.dat file the contents are totally illegible, for example: ú9äÈ?TAp <?%Œ  ü:äÈ?z3Ap <?%Œ

    Any tips on how to proceed?

    Thanks,

    Peter.

     
  • barrykgerdes
    barrykgerdes
    2014-02-22

    Briefly adding images of your own of deep sky objects is a rather complicated procedure. The image must preferably first be processed and sized to a square with sides 64, 128, 256, 512 or 1024 pixels with the background of the sky black (to make it blend into the display)

    I process my textures in photoshop (expensive) or TheGmp (Free)

    Next you need to plate solve the corner coordinates to make an entry into the textures.json file. There are probably programs around that can do this but I usually resort to manually tweaking this using the old DSS real sky program to identify the corners and get the corners exact so that the texture perfectly overlays the stars of Stellarium. I then have a little program that these cordinates can be entered into to generate an entry for the textures.json file.

    See section 5.8 in this user manual

    http://barry.sarcasmogerdes.com/stellarium/stellarium_user_guide-new.pdf

    Barry

     

  • Anonymous
    2014-02-22

    Thanks, Barry, sounds tricky but not impossible. I have Photoshop, and a recently acquired SkyX which might do the plate solve although I haven't got to grips with it yet. Steep learning curve! Stellarium is IMHO much nicer for general use, particularly for talks and outreach.

    Alexander, don't be so negative! Of course I read the User Guide, how do you think I knew to look in the ngc2000.dat file? The User Guide states "The file is a plain ASCII file and may be edited with a normal text editor". But the entries are not in a directly readable form. Presumably each character is used to represent its ASCII value in the data set and thereby keep the file size down to a minimum. But unless there is some routine available to code/decode each string, creating new entries using an ASCII table will be nightmarish!

    So I ask again, any tips?? I have numerous decent images of my own, and it would be nice to have them in Stellarium. But unfortunately looks like a major effort.

    Peter.
    http://www.madpc.co.uk/~peterv

     
    • Alexander Wolf
      Alexander Wolf
      2014-02-23

      Alexander, don't be so negative! Of course I read the User Guide, how do you think I knew to look in the ngc2000.dat file? The User Guide states "The file is a plain ASCII file and may be edited with a normal text editor". But the entries are not in a directly readable form. Presumably each character is used to represent its ASCII value in the data set and thereby keep the file size down to a minimum. But unless there is some routine available to code/decode each string, creating new entries using an ASCII table will be nightmarish!

      Really? Quote from section "Adding Nebulae Images" ( http://www.stellarium.org/wiki/index.php/Adding_Nebulae_Images ):

      If you wish to associate a texture (image) with the object, you must also add a record to the.../nebulae/default/textures.json file.

      Now explain, please, why you tried edit ngc2000.dat?

       

  • Anonymous
    2014-02-23

    Hi Peter
    The ngc2000.dat file is not necessary for what you want to do. You probably have an early version of the user guide. The file is no longer ASCII. It has been compressed. However an entry in the NGC2000names.dat may help. In any case the NGC2000.dat only contains the standard NGC/Ic list of the normal 13224 entries. Get the user guide I gave the link to.

    The only thing necessary to add a texture for display is what I outlined previously.

    I also have a much larger nebula folder with many more textures which I can make available so you don't need to duplicate what I already have done.

    Barry

     
  • barrykgerdes
    barrykgerdes
    2014-02-23

    I just posted another response but I had not noticed my login had expired

    Barry

     

    • Anonymous
      2014-02-23

      Hi, guys,

      Alexander, you say "Now explain, please, why you tried edit ngc2000.dat?"

      Because in the (latest version) User Guide it states "To add a new extended object add an entry in the ..ngc2000.dat file with the details of the object". Need I say more?

      Barry, thanks for the update - that the file has been compressed clarifies the situation, but of course also makes it difficult to add anything there. On the other hand with 13224 NGC objects I guess things are pretty well covered ;-)

      Thank you for the offer of your textures file. Gratefully accepted. You can find my email address on my web site so we can discuss off Forum how to get it to me.

      I'll have a go at a DIY texture, but suspect I won't have much success. I did eventually manage to get my own landscape up and running so that was a small victory!

      Best regards,

      Peter

      http://www.madpc.co.uk/~peterv

       
      • Alexander Wolf
        Alexander Wolf
        2014-02-23

        Because in the (latest version) User Guide it states "To add a new extended object add an entry in the ..ngc2000.dat file with the details of the object". Need I say more?

        facepalm again :) Do you really want add new object? Just for understanding - if you want add texture for NGC 1000 (as example) then why you tried add another record NGC 1000 into NGC/IC catalog?

        I know - I was asshole, but why you read "To add a new extended object" as "To add a texture for object"? More, in next paragraph you read about adding new proper names for DSO, and in next paragraph - how add textures for DSO. But you ignore it and tried edit fully wrong file.

        English is not mother language for me (I really don't speak English language :) ) but I don't have troubles with understanding of this chapter of the User Guide.

         

  • Anonymous
    2014-02-24

    Hi, Alexander,

    There are many objects not classified as NGC/IC - Sharpless, Arp, Van den Bergh etc. No matter, Barry has very kindly made his larger nebula folder available, and has amended the User Guide. There may be other NGC objects I might wish to add - I'll probably have a go, but if I fail, so be it.

    Peter.

     
  • barrykgerdes
    barrykgerdes
    2014-02-24

    Hi Peter

    Yes there are some none NGC images in my package but they all display correctly as long as the details are in the textures.json file. You just need the the name of your image and its corner coordinates.

    Barry

     


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