Minor changes

measure.c

@@ -412,6 +412,7 @@ int main(int argc,char *argv[])
   int year;
   float frac=0.5;
   float fx=0.5,fy=0.333;
+  int ix=0,iy=0;
 
   // Environment variables
   env=getenv("ST_DATADIR");
@@ -538,6 +539,7 @@ int main(int argc,char *argv[])
       redraw=1;
       continue;
     }
+
     // Center
     if (c=='c') {
       xmin=x-fx*width;
@@ -558,6 +560,33 @@ int main(int argc,char *argv[])
       continue;
     }
 
+    // Cycle through image
+    if (c=='\t') {
+      printf("%d %d\n",ix,iy);
+
+      // Set area
+      width=1000;
+      x=width*(ix+0.5);
+      y=width*(iy+0.5);
+      xmin=x-fx*width;
+      xmax=x+fx*width;
+      ymin=y-fy*width;
+      ymax=y+fy*width;
+
+      // Increment
+      ix++;
+      if (width*ix>img.naxis1) {
+	ix=0;
+	iy++;
+      }
+      if (width*iy>img.naxis2) {
+	ix=0;
+	iy=0;
+      }
+      redraw=1;
+      continue;
+    }
+
 
 
     // Zoom

skymap.c

@@ -49,7 +49,7 @@ struct sat {
   double rsun,rearth,h;
   double psun,pearth,p,phase;
   double r,v,ra,de;
-  double azi,alt;
+  double azi,alt,salt;
   double rx,ry;
 };
 struct star {
@@ -1436,8 +1436,12 @@ void skymap_plotsatellite(char *filename,int satno,double mjd0,double dt)
 	  if (Isat==priority[i]) {
 	    cpgsci(2);
 	    break;
-	  } else
-	    cpgsci(7);
+	  } else {
+	    if (s.salt<0.0)
+	      cpgsci(7);
+	    else
+	      cpgsci(8);
+	  }
 	}
       }
 
@@ -1565,7 +1569,7 @@ struct sat apparent_position(double mjd)
   double jd,rsun,rearth,rsat;
   double dx,dy,dz,dvx,dvy,dvz;
   xyz_t satpos,obspos,obsvel,satvel,sunpos;
-  double sra,sde;
+  double sra,sde,azi;
 
   // Sat ID
   s.Isat=Isat;
@@ -1578,6 +1582,9 @@ struct sat apparent_position(double mjd)
   satpos_xyz(jd,&satpos,&satvel);
   sunpos_xyz(mjd,&sunpos,&sra,&sde);
 
+  // Sun altitude
+  equatorial2horizontal(mjd,sra,sde,&azi,&s.salt);
+ 
   // Age
   s.age=jd-SGDP4_jd0;