/* look up which star atlas an ra/dec is in. * Urano and Mill contributed by Atsuo Ohki * U2K by Robert Lane * * N.B. skylist.c assumes a certain max length for any returned string. */ #include #include #include "astro.h" /* for Millennium Star Atlas */ static int msa_charts[] = { /* 90*/ 2, /* 84*/ 4, /* 78*/ 8, /* 72*/ 10, /* 66*/ 12, /* 60*/ 14, /* 54*/ 16, /* 48*/ 20, /* 42*/ 20, /* 36*/ 22, /* 30*/ 22, /* 24*/ 24, /* 18*/ 24, /* 12*/ 24, /* 6*/ 24, /* 0*/ 24, /* -6*/ 24, /*-12*/ 24, /*-18*/ 24, /*-24*/ 24, /*-30*/ 22, /*-36*/ 22, /*-42*/ 20, /*-48*/ 20, /*-54*/ 16, /*-60*/ 14, /*-66*/ 12, /*-72*/ 10, /*-78*/ 8, /*-84*/ 4, /*-90*/ 2 }; /* * find the chart number of Millennium Star Atlas and return pointer to static * string describing location. * 0 <= ra < 24; -90 <= dec <= 90 */ char * msa_atlas(double ra, double dec) { static char buf[512]; int zone, band; int i, p; ra = radhr(ra); dec = raddeg(dec); buf[0] = 0; if (ra < 0.0 || 24.0 <= ra || dec < -90.0 || 90.0 < dec) return (buf); zone = (int)(ra/8.0); band = -((int)(dec+((dec>=0)?3:-3))/6 - 15); for (p=0, i=0; i <= band; i++) p += msa_charts[i]; i = (int)((ra - 8.0*zone) / (8.0/msa_charts[band])); sprintf(buf, "V%d - P%3d", zone+1, p-i+zone*516); return (buf); } /* for original Uranometria */ static struct { double l; int n; } um_zones[] = { /* 84 - 90 */ { 84.5, 2}, /* 72 - 85 */ { 72.5, 12}, /* 60 - 73 */ { 61.0, 20}, /* 49 - 62 */ { 50.0, 24}, /* 38 - 51 */ { 39.0, 30}, /* 27 - 40 */ { 28.0, 36}, /* 16 - 29 */ { 17.0, 45}, /* 5 - 18 */ { 5.5, 45}, /* 0 - 6 */ { 0.0, 45}, { 0.0, 0} }; /* * find the chart number of Uranometria first edition and return pointer to * static string describing location. * 0 <= ra < 24; -90 <= dec <= 90 */ char * um_atlas(double ra, double dec) { static char buf[512]; int band, south; int p; double w; ra = radhr(ra); dec = raddeg(dec); buf[0] = 0; if (ra < 0.0 || 24.0 <= ra || dec < -90.0 || 90.0 < dec) return (buf); p = 0; if (dec < 0.0) { dec = -dec; south = 1; } else south = 0; p = 1; for (band=0; um_zones[band].n; band++) { if (um_zones[band].l <= dec) break; p += um_zones[band].n; } if (!um_zones[band].n) return (buf); w = 24.0 / um_zones[band].n; if (band) { ra += w/2.0; if (ra >= 24.0) ra -= 24.0; } if (south && um_zones[band+1].n) p = 475 - p - um_zones[band].n; if (south && band == 0) { /* south pole part is mis-ordered! */ ra = 24.0 - ra; } sprintf(buf, "V%d - P%3d", south+1, p+(int)(ra/w)); return (buf); } /* for Uranometria 2000.0 */ static struct { double lowDec; /* lower dec cutoff */ int numZones; /* number of panels (aka zones) */ } u2k_zones[] = { /* array of book layout info */ /* 84 - 90 */ { 84.5, 1}, /* lower dec cutoff, # of panels in band */ /* 73 - 85 */ { 73.5, 6}, /* 62 - 74 */ { 62.0, 10}, /* 51 - 63 */ { 51.0, 12}, /* 40 - 52 */ { 40.0, 15}, /* 29 - 41 */ { 29.0, 18}, /* 17 - 30 */ { 17.0, 18}, /* 5 - 18 */ { 5.5, 20}, /* 0 - 6 */ { 0.0, 20}, { 0.0, 0} /*numZones value in this line is a stopper.*/ }; /* find the chart number of Uranometria 2000.0 and return pointer to static * string describing location. * 0 <= ra < 24; -90 <= dec <= 90 */ char * u2k_atlas(double ra, double dec) { static char buf[512]; static char err[] = "???"; int band; /* index to array */ int south; /* flag for volume 2*/ int panel; /* panel number */ ra = radhr(ra); dec = raddeg(dec); buf[0] = 0; if (ra < 0.0 || 24.0 <= ra || dec < -90.0 || 90.0 < dec) { strcpy (buf, err); return (buf); /* range checking */ } if (dec < 0.0) { dec = -dec; south = 1; /* South is mirror of North */ } else south = 0; panel = 1; band = 0; /* scan u2k_zones for the correct band: */ while (u2k_zones[band].numZones != 0 && dec <= u2k_zones[band].lowDec ){ panel += u2k_zones[band].numZones; /*accumulate total panels */ band++ ; } if (!u2k_zones[band].numZones) { /* hit end of array with no match. */ strcpy (buf, err); return (buf); } ra -= 12.0 / u2k_zones[band].numZones; /*offset by half-width of panel*/ if (ra >= 24.0) /* reality check. shouldn't happen. */ ra -= 24.0; if (ra < 0.0) /* offset could give negative ra */ ra += 24.0; if (south && u2k_zones[band+1].numZones) panel = 222 - panel - u2k_zones[band].numZones; /* resultant panel number is accumulated panels in prior bands plus * ra's fraction of panels in dec's band. panel # goes up as ra goes * down. */ sprintf(buf, "V%d - P%3d", south+1, panel+(int)(u2k_zones[band].numZones*(24.0 - ra)/24.0)); return (buf); } /* For RCS Only -- Do Not Edit */ static char *rcsid[2] = {(char *)rcsid, "@(#) $RCSfile: atlas.c,v $ $Date: 2005-08-21 10:02:36 $ $Revision: 1.3 $ $Name: not supported by cvs2svn $"};