sys/src/cmd/astro/search.c

   1 #include "astro.h"
   2
   3 char*   solstr[] =
   4 {
   5         "Fall equinox",
   6         "Winter solstice",
   7         "Spring equinox",
   8         "Summer solstice",
   9 };
  10
  11 struct
  12 {
  13         double  beta;
  14         int     rta;
  15         int     dec;
  16         char    *betstr;
  17 } bettab[] =
  18 {
  19         -1.3572, 231,   50,     "Quadrantid",
  20          0.7620, 336,   0,      "Eta aquarid",
  21          1.5497, 260,   -20,    "Ophiuchid",
  22          2.1324, 315,   -15,    "Capricornid",
  23          2.1991, 339,   -17,    "Delta aquarid",
  24          2.2158, 340,   -30,    "Pisces australid",
  25          2.4331, 46,    58,     "Perseid",
  26         -2.6578, 95,    15,     "Orionid",
  27         -1.8678, 15,    -55,    "Phoenicid",
  28         -1.7260, 113,   32,     "Geminid",
  29         0
  30 };
  31
  32 void
  33 search(void)
  34 {
  35         Obj2 *p, *q;
  36         int i, j;
  37         double t;
  38
  39         for(i=0; objlst[i]; i++) {
  40                 p = objlst[i];
  41                 if(p == &oshad)
  42                         continue;
  43                 t = rise(p, -.833);
  44                 if(t >= 0.)
  45                         event("%s rises at ", p->name, "", t,
  46                                 i==0? PTIME: PTIME|DARK);
  47                 t = set(p, -.833);
  48                 if(t >= 0.)
  49                         event("%s sets at ", p->name, "", t,
  50                                 i==0? PTIME: PTIME|DARK);
  51                 if(p == &osun) {
  52                         for(j=0; j<4; j++) {
  53                                 t = solstice(j);
  54                                 if(t >= 0)
  55                                         event("%s at ", solstr[j], "", t,
  56                                                 SIGNIF|PTIME);
  57                         }
  58                         for(j=0; bettab[j].beta!=0; j++) {
  59                                 t = betcross(bettab[j].beta);
  60                                 if(t >= 0)
  61                                         event("%s meteor shower",
  62                                         bettab[j].betstr, "", t, SIGNIF);
  63                         }
  64                         t = rise(p, -18);
  65                         if(t >= 0)
  66                                 event("Twilight starts at ", "", "", t, PTIME);
  67                         t = set(p, -18);
  68                         if(t >= 0)
  69                                 event("Twilight ends at ", "", "", t, PTIME);
  70                 }
  71                 if(p == &omoon)
  72                 for(j=0; j<NPTS; j++) {
  73                         if(p->point[j].mag > .75 && p->point[j+1].mag < .25)
  74                                 event("New moon", "", "", 0, 0);
  75                         if(p->point[j].mag <= .25 && p->point[j+1].mag > .25)
  76                                 event("First quarter moon", "", "", 0, 0);
  77                         if(p->point[j].mag <= .50 && p->point[j+1].mag > .50)
  78                                 event("Full moon", "", "", 0, 0);
  79                         if(p->point[j].mag <= .75 && p->point[j+1].mag > .75)
  80                                 event("Last quarter moon", "", "", 0, 0);
  81                 }
  82                 if(p == &omerc || p == &ovenus) {
  83                         t = melong(p);
  84                         if(t >= 0) {
  85                                 t = rise(p, 0) - rise(&osun, 0);
  86                                 if(t < 0)
  87                                         t += NPTS;
  88                                 if(t > NPTS)
  89                                         t -= NPTS;
  90                                 if(t > NPTS/2)
  91                                 event("Morning elongation of %s", p->name,
  92                                         "", 0, SIGNIF);
  93                                 else
  94                                 event("Evening elongation of %s", p->name,
  95                                         "", 0, SIGNIF);
  96                         }
  97                 }
  98                 for(j=i; objlst[j]; j++) {
  99                         if(i == j)
 100                                 continue;
 101                         q = objlst[j];
 102                         if(p == &omoon || q == &omoon) {
 103                                 occult(p, q, 0);
 104                                 if(occ.t3 < 0)
 105                                         continue;
 106                                 if(p == &osun || q == &oshad) {
 107                                         if(occ.t1 >= 0)
 108                                         event("Partial eclipse of %s begins at ", p->name, "",
 109                                                 occ.t1, SIGNIF|PTIME);
 110                                         if(occ.t2 >= 0)
 111                                         event("Total eclipse of %s begins at ", p->name, "",
 112                                                 occ.t2, SIGNIF|PTIME);
 113                                         if(occ.t4 >= 0)
 114                                         event("Total eclipse of %s ends at ", p->name, "",
 115                                                 occ.t4, SIGNIF|PTIME);
 116                                         if(occ.t5 >= 0)
 117                                         event("Partial eclipse of %s ends at ", p->name, "",
 118                                                 occ.t5, SIGNIF|PTIME);
 119                                 } else {
 120                                         if(occ.t1 >= 0)
 121                                         event("Occultation of %s begins at ", q->name, "",
 122                                                 occ.t1, SIGNIF|PTIME);
 123                                         if(occ.t5 >= 0)
 124                                         event("Occultation of %s ends at ", q->name, "",
 125                                                 occ.t5, SIGNIF|PTIME);
 126                                 }
 127                                 continue;
 128                         }
 129                         if(p == &osun) {
 130                                 if(q != &omerc && q != &ovenus)
 131                                         continue;
 132                                 occult(p, q, -1);
 133                                 if(occ.t3 >= 0.) {
 134                                         if(occ.t1 >= 0)
 135                                         event("Transit of %s begins at ", q->name, "",
 136                                                 occ.t1, SIGNIF|LIGHT|PTIME);
 137                                         if(occ.t5 >= 0)
 138                                         event("Transit of %s ends at ", q->name, "",
 139                                                 occ.t5, SIGNIF|LIGHT|PTIME);
 140                                 }
 141                                 continue;
 142                         }
 143                         t = dist(&p->point[0], &q->point[0]);
 144                         if(t > 5000)
 145                                 continue;
 146                         event("%s is in the house of %s",
 147                                 p->name, q->name, 0, 0);
 148                 }
 149         }
 150         if(flags['o'])
 151                 stars();
 152         if(flags['a'])
 153                 satels();
 154         evflush();
 155 }