Issues Changing the Stars

[Hungry4info]

And thus I am here again, complaining of problems that could be easily resolved if I had more than 3 brain cells...

I'm using Celestia 1.5.0pre-release1.
I'm kind-of working on an add-on that inserts a lot of binary stars into celestia, as well as updates some. I did research, found enough information on Sigma2 CrB to put it into celestia. I figured Celestia already had the star, so I went in and checked out the system. As I suspected, it had the main star, but not the smaller companion. (the 2mil star catalogue shows a companion at ~500 AU, but this isn't the companion that I wish to add. I'm adding on for ~0.2 AU away).

Either I need to do two things;
1) Remove Sigma2 CrB from Celestia, and make an STC for it.
2) Use the "Modify" parameter to adjust the pre-existing star. Problem is, I had already tried this when I tried to add the companion to Mira a few months back. I could not get anywhere with it. I'd much rather do this than remove Sigma2 CrB from Celestia.

I apologize for bothering people with such trivial matters, but is it possible somebody could post on this thread a barycenter that modifys a pre-existing single star?

While I'm here... anybody have a good model I can use for a contact binary? There'll be several I need to do...

[selden]

/data/spectbin.stc and /data/viaualbins.stc redefine many stars as binaries.

Essentially you specify the HIP number in an STC file and it replaces all of that star's parameters. You have to provide them all. There's no Replace or Modify declaration as in SSC files, nor a Delete for either

Medusa posted an STC that defines a near-contact binary. No models are required. See
http://www.celestiaproject.net/forum/viewtopic ... ht=sheliak

[Hungry4info]

Ah, okay. Thank you very much for that.

EDIT:

Time to annoy you... again... with a problem:

I put the SIG CrB system into celestia. Unfortunately, I didn't realise that Sig and SIG aren't the same, so my double star system revolved around the original star. Other than that, it was at the exact place in the sky I wanted it =D. After a few hours of searching for, then finding my error, I capitalized "Sig", went into Celestia (again, v1.5.0pre1). It looked good, everything was right. Except... now, it's no longer in Coronae Borealis, but in Andromedae. If it helps, here's my stc (With big help from Medusa):

Code: Select all

Barycenter "SIG CrB:17 CrB:HIP 79607:HD 146361:SAO 65165:TYC 2583-1846-1"
   {
     RA        16.244681
     Dec        33.85861
     Distance   70.738
   }
   
"SIG CrB A:17 CrB A:HIP 79607 A:HD 146361 A:SAO 65165 A:TYC 2583-1846-1 A"
   {
     OrbitBarycenter "17 CrB"
     EllipticalOrbit
      {
        Period          1.14
        SemiMajorAxis   0.028
        Inclination     -60
        ArgOfPericenter 0
      }
     SpectralType       "F6V"
     AppMag             5.3
     Obliquity          -60
   }
   
"SIG CrB B:17 CrB B:HIP 79607 A:HD 146361 B:SAO 65165 B:TYC 2583-1846-1 B"
   {
     OrbitBarycenter "17 CrB"
     EllipticalOrbit
      {
        Period          1.14
        SemiMajorAxis   0.028
        Inclination     -60
        ArgOfPericenter 180
      }
     SpectralType       "G0V"
     AppMag             5.3
     Obliquity          -60
   }


[Hungry4info]

Any advice?

[selden]

1. STC files require the RA to be specified in degrees. You've specified it in Hours. That's why the star now is in the wrong constellation. Multiply Hours by 15 to get degrees.

2. There's a typo in the list of names for the B star.
:HIP 79607 A: should be :HIP 79607 B:

[Hungry4info]

Thank you very much. I have made the corrections you suggested:

Code: Select all

Barycenter "SIG CrB:17 CrB:HIP 79607:HD 146361:SAO 65165:TYC 2583-1846-1"
   {
     Ra        16.244681
     Dec        33.85861
     Distance   70.738
   }
   
"SIG CrB A:17 CrB A:HIP 79607 A:HD 146361 A:SAO 65165 A:TYC 2583-1846-1 A"
   {
     OrbitBarycenter "17 CrB"
     EllipticalOrbit
      {
        Period          1.14
        SemiMajorAxis   0.028
        Inclination     -60
        ArgOfPericenter 0
      }
     SpectralType       "F6V"
     AppMag             5.3
     # Radius             10000000
     Obliquity          -60
   }
   
"SIG CrB B:17 CrB B:HIP 79607 A:HD 146361 B:SAO 65165 B:TYC 2583-1846-1 B"
   {
     OrbitBarycenter "17 CrB"
     EllipticalOrbit
      {
        Period          1.14
        SemiMajorAxis   0.028
        Inclination     -60
        ArgOfPericenter 180
      }
     SpectralType       "G0V"
     AppMag             5.3
     # Radius             8000000
     RotationPeriod     309.8399679
     Obliquity          -60
   }


Now the problem is that the original star still exists.

[selden]

To replace an existing cataloged star, you need to specify its HIP catalog number as a separate number:

Code: Select all

Barycenter 79607 "SIG CrB:17 CrB:HIP 79607:HD 146361:SAO 65165:TYC 2583-1846-1"


[Hungry4info]

I copied what you wrote into my STC:

Code: Select all

Barycenter 79607 "SIG CrB:17 CrB:HIP 79607:HD 146361:SAO 65165:TYC 2583-1846-1"
   {
     Ra        16.244681
     Dec        33.85861
     Distance   70.738
   }
   
"SIG CrB A:17 CrB A:HIP 79607 A:HD 146361 A:SAO 65165 A:TYC 2583-1846-1 A"
   {
     OrbitBarycenter "17 CrB"
     EllipticalOrbit
      {
        Period          1.14
        SemiMajorAxis   0.028
        Inclination     -60
        ArgOfPericenter 0
      }
     SpectralType       "F6V"
     AppMag             5.3
     # Radius             10000000
     Obliquity          -60
   }
   
"SIG CrB B:17 CrB B:HIP 79607 A:HD 146361 B:SAO 65165 B:TYC 2583-1846-1 B"
   {
     OrbitBarycenter "17 CrB"
     EllipticalOrbit
      {
        Period          1.14
        SemiMajorAxis   0.028
        Inclination     -60
        ArgOfPericenter 180
      }
     SpectralType       "G0V"
     AppMag             5.3
     # Radius             8000000
     RotationPeriod     309.8399679
     Obliquity          -60
   }


Unfortunately, the original star still remains. So I tried a few things:
1) I tried giving the first star the 79607 prefix as well. Celestia didn't like that too much. When I selected the star, it closed itself.
2) I tried giving the first star this alteration:

Code: Select all

79607A "SIG CrB A:17 CrB A:HIP 79607 A:HD 146361 A:SAO 65165 A:TYC 2583-1846-1 A"


As well as a similar thing for the second star. I went into Celestia, and neither of the stars existed (but the original remained). I suppose Celestia doesn't like non-numerical characters for that first number. I searched for another STC laying around that might be generating the star I'm trying to destroy. I searched for any file (Start -> Search -> Files and Folders -> "A word or phrase in the file") containing the phrases "SIG CrB", "79607", and "146361", but no files, including the one I'm working on now, showed up.

Why is the original star still there? and what further can I do to remove it?

(I sincerely apologize for being such a pain in the rear)

[selden]

The problem is revealed in Celestia's "console log". You can toggle it on and off by typing a tilde (~). Use the up and down arrow keys to navigate in it.

It says (near the top)

Code: Select all

Loading star catalog: extras/sigcr.stc
Invalid star: missing right ascension

RA must be spelled with both letters capitalized.
This error prevents your Barycenter from being defined, so Celestia continues to use the previous Star definition.

[Hungry4info]

Ah, another capitalization error. It all works properly now, thank you very much.

[ajtribick]

BTW if you just specify the number, then the naming information is carried across.

So you can just write

Code: Select all

Barycenter 79607
{
...put star information here...
}


instead of

Code: Select all

Barycenter 79607 "SIG CrB:17 CrB:HIP 79607:HD 146361:SAO 65165:TYC 2583-1846-1"
{
...put star information here...
}


[Hungry4info]

Ooohhh... okay. If I want to add names, such as the TYC numbers, I just
write it...

Code: Select all

Barycenter 79607 "TYC ###-####-#"
{
...put star information here...
}


... like that?