<p>I'm trying to develop a planetarium using <a href="https://en.wikipedia.org/wiki/Tycho-2_Catalogue" rel="nofollow">Tycho 2 catalogue</a>.</p>

<p>To read it I use the <a href="http://tdc-www.harvard.edu/catalogs/tycho2.html" rel="nofollow">WCSTools</a>. But I have a problem.</p>

<p>On Wikipedia I have found that Rigel star has RA: 05h 14min 32,3s and Dec: -08º 12’ 06’’. I have translate them to decimal degrees (78.6375, -8.2017). I've used that to find it on Tycho 2 catalogue (file catalog.dat) but I can't find it.</p>

<p>To search into the catalogue I have used the function TY2READ from <a href="https://github.com/kapadia/PinpointWCS/blob/master/libwcs/ty2read.c" rel="nofollow">ty2read.c</a> file.</p>

<p>And this is how I search the star:</p>

<pre><code>void ReadTy2Catalog()
{
    double raCenter = 84.5;
    double decCenter = -1.2;
    double raDistance = 10.;
    double decDistance = 10.;

    int nMaxStars = 20000;

    char* filePath = "D:\\Fuentes\\Repos\\Planetarium\\StarsCataloguesLib\\Resources\\";
    Ty2Read read;

    read.Read(
        filePath,
        TYCHO2,         /* Catalog code from wcscat.h */
        raCenter,       /* Search center J2000 right ascension in degrees */
        decCenter,      /* Search center J2000 declination in degrees */
        raDistance,     /* Search half width in right ascension in degrees */
        decDistance,    /* Search half-width in declination in degrees */
        0,              /* Limiting separation in degrees (ignore if 0) */
        0,              /* Inner edge of annulus in degrees (ignore if 0) */
        1,              /* 1 to sort stars by distance from center */
        WCS_J2000,      /* Search coordinate system */
        2000.0,         /* Search coordinate equinox */
        0.0,            /* Proper motion epoch (0.0 for no proper motion) */
        -20.0,          /* Limiting magnitudes (none if equal) */
        30.0,           /* Limiting magnitudes (none if equal) */
        1,              /* Magnitude by which to sort (1 or 2) */
        nMaxStars,      /* Maximum number of stars to be returned */
        1);             /* Verbose*/
}
</code></pre>

<p>I have checked all the stars returned and none has Rigel's RA and DEC.</p>

<p>What am I doing wrong?</p>

<software><astrometry>
I can't find Rigel on Tycho 2 catalogue
VansFannel
# I can't find Rigel on Tycho 2 catalogue

(Asked by: username_0 on 2015-11-01)

I'm trying to develop a planetarium using Tycho 2 catalogue.
To read it I use the WCSTools. But I have a problem.
On Wikipedia I have found that Rigel star has RA: 05h 14min 32,3s and Dec: -08º 12’ 06’’. I have translate them to decimal degrees (78.6375, -8.2017). I've used that to find it on Tycho 2 catalogue (file catalog.dat) but I can't find it.
To search into the catalogue I have used the function TY2READ from ty2read.c file.
And this is how I search the star:
void ReadTy2Catalog()
{
    double raCenter = 84.5;
    double decCenter = -1.2;
    double raDistance = 10.;
    double decDistance = 10.;

    int nMaxStars = 20000;

    char* filePath = "D:\\Fuentes\\Repos\\Planetarium\\StarsCataloguesLib\\Resources\\";
    Ty2Read read;

    read.Read(
        filePath,
        TYCHO2,         /* Catalog code from wcscat.h */
        raCenter,       /* Search center J2000 right ascension in degrees */
        decCenter,      /* Search center J2000 declination in degrees */
        raDistance,     /* Search half width in right ascension in degrees */
        decDistance,    /* Search half-width in declination in degrees */
        0,              /* Limiting separation in degrees (ignore if 0) */
        0,              /* Inner edge of annulus in degrees (ignore if 0) */
        1,              /* 1 to sort stars by distance from center */
        WCS_J2000,      /* Search coordinate system */
        2000.0,         /* Search coordinate equinox */
        0.0,            /* Proper motion epoch (0.0 for no proper motion) */
        -20.0,          /* Limiting magnitudes (none if equal) */
        30.0,           /* Limiting magnitudes (none if equal) */
        1,              /* Magnitude by which to sort (1 or 2) */
        nMaxStars,      /* Maximum number of stars to be returned */
        1);             /* Verbose*/
}

I have checked all the stars returned and none has Rigel's RA and DEC.
What am I doing wrong?

**Tags:** software, astrometry

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## 0 answers

