diff --git a/src/calcelestial.c b/src/calcelestial.c
index f520eb2..8baffb6 100644
--- a/src/calcelestial.c
+++ b/src/calcelestial.c
@@ -119,6 +119,7 @@ int main(int argc, char *argv[]) {
 	int tz = INT_MAX;
 //	char *format = "time: %Y-%m-%d %H:%M:%S az: §a (§s) alt: §h";
 	char *format = "%H:%M";
+	char *obj_str = basename(argv[0]);
 	char *query = NULL;
 	bool error = false;
 	bool utc = false;
@@ -134,9 +135,6 @@ int main(int argc, char *argv[]) {
 	struct ln_lnlat_posn obs = { DBL_MAX, DBL_MAX };
 	struct object_details result;
 
-	/* parse planet/obj */
-	obj = object_from_name(basename(argv[0]));
-
 	/* parse command line arguments */
 	while (1) {
 		int c = getopt_long(argc, argv, "+hvnut:d:f:a:o:q:z:p:m:H:", long_options, NULL);
@@ -210,7 +208,7 @@ int main(int argc, char *argv[]) {
 #endif
 
 			case 'p':
-				obj = object_from_name(optarg);
+				obj_str = optarg;
 				break;
 
 			case 'z':
@@ -236,12 +234,11 @@ int main(int argc, char *argv[]) {
 				error = true;
 		}
 	}
-
-	/* validate obj */
-	if (obj == OBJECT_INVALID) {
-		fprintf(stderr, "invalid object, use --object\n");
-		error = true;
-	}
+	
+	/* Parse planet/obj */
+	obj = object_lookup(obj_str);
+	if (!obj)
+		usage_error("invalid or missing object, use --object");
 
 #ifdef GEONAMES_SUPPORT
 	/* lookup place at http://geonames.org */
diff --git a/src/objects.c b/src/objects.c
index 845b5a4..18db378 100644
--- a/src/objects.c
+++ b/src/objects.c
@@ -27,133 +27,53 @@
 
 #include "objects.h"
 
-const char* objects[] = {
-	NULL, /* invalid */
-	"sun",
-	"moon",
-	"mars",
-	"neptune",
-	"jupiter",
-	"mercury",
-	"uranus",
-	"saturn",
-	"venus",
-	"pluto"
+static struct object {
+	const char *name;
+	int (*rst)(double JD, struct ln_lnlat_posn *observer, struct ln_rst_time *rst);
+	void (*equ_coords)(double JD, struct ln_equ_posn *position);
+	double (*earth_dist)(double JD);
+	double (*sdiam)(double JD);
+} objects[] = {
+	{ "sun",     0 /* special case */, ln_get_solar_equ_coords,   ln_get_earth_solar_dist,   ln_get_solar_sdiam       },
+	{ "moon",    ln_get_lunar_rst,     ln_get_lunar_equ_coords,   ln_get_lunar_earth_dist,   ln_get_lunar_sdiam       },
+	{ "mars",    ln_get_mars_rst,      ln_get_mars_equ_coords,    ln_get_mars_earth_dist,    ln_get_mars_sdiam        },
+	{ "neptune", ln_get_neptune_rst,   ln_get_neptune_equ_coords, ln_get_neptune_earth_dist, ln_get_neptune_sdiam     },
+	{ "jupiter", ln_get_jupiter_rst,   ln_get_jupiter_equ_coords, ln_get_jupiter_earth_dist, ln_get_jupiter_equ_sdiam },
+	{ "mercury", ln_get_mercury_rst,   ln_get_mercury_equ_coords, ln_get_mercury_earth_dist, ln_get_mercury_sdiam     },
+	{ "uranus",  ln_get_uranus_rst,    ln_get_uranus_equ_coords,  ln_get_uranus_earth_dist,  ln_get_uranus_sdiam      },
+	{ "saturn",  ln_get_saturn_rst,    ln_get_saturn_equ_coords,  ln_get_saturn_earth_dist,  ln_get_saturn_equ_sdiam  },
+	{ "venus",   ln_get_venus_rst,     ln_get_venus_equ_coords,   ln_get_venus_earth_dist,   ln_get_venus_sdiam       },
+	{ "pluto",   ln_get_pluto_rst,     ln_get_pluto_equ_coords,   ln_get_pluto_earth_dist,   ln_get_pluto_sdiam       }
 };
 
-void object_pos(enum object obj, double jd, struct object_details *details) {
-	switch (obj) {
-		case OBJECT_SUN:	return object_pos_sun(jd, details);
-		case OBJECT_MOON:	return object_pos_moon(jd, details);
-		case OBJECT_MARS:	return object_pos_mars(jd, details);
-		case OBJECT_NEPTUNE:	return object_pos_neptune(jd, details);
-		case OBJECT_JUPITER:	return object_pos_jupiter(jd, details);
-		case OBJECT_MERCURY:	return object_pos_mercury(jd, details);
-		case OBJECT_URANUS:	return object_pos_uranus(jd, details);
-		case OBJECT_SATURN:	return object_pos_saturn(jd, details);
-		case OBJECT_VENUS:	return object_pos_venus(jd, details);
-		case OBJECT_PLUTO:	return object_pos_pluto(jd, details);
-		default: ;
-	}
-}
-
-int object_rst(enum object obj, double jd, double horizon, struct ln_lnlat_posn *obs, struct ln_rst_time *rst) {
-	switch (obj) {
-		case OBJECT_SUN:	return ln_get_solar_rst_horizon(jd, obs, horizon, rst);
-		case OBJECT_MOON:	return ln_get_lunar_rst(jd, obs, rst);
-		case OBJECT_MARS:	return ln_get_mars_rst(jd, obs, rst);
-		case OBJECT_NEPTUNE:	return ln_get_neptune_rst(jd, obs, rst);
-		case OBJECT_JUPITER:	return ln_get_jupiter_rst(jd, obs, rst);
-		case OBJECT_MERCURY:	return ln_get_mercury_rst(jd, obs, rst);
-		case OBJECT_URANUS:	return ln_get_uranus_rst(jd, obs, rst);
-		case OBJECT_SATURN:	return ln_get_saturn_rst(jd, obs, rst);
-		case OBJECT_VENUS:	return ln_get_venus_rst(jd, obs, rst);
-		case OBJECT_PLUTO:	return ln_get_pluto_rst(jd, obs, rst);
-		default:		return -1;
-	}
-}
-
-enum object object_from_name(const char *name) {
+const struct object * object_lookup(const char *name)
+{
 	int c;
-	for (c = 1; c <= OBJECTS; c++) {
-		if (strcmp(objects[c], name) == 0) {
-			return (enum object) c;
-		}
+	for (c = 0; c <= sizeof(objects) / sizeof(objects[0]); c++) {
+		if (strcmp(objects[c].name, name) == 0)
+			return &objects[c];
 	}
 
-	return OBJECT_INVALID;
+	return NULL;
 }
 
-const char * object_to_name(enum object obj) {
-	return objects[obj];
+const char * object_name(const struct object *o)
+{
+	return o->name;
 }
 
-void object_pos_sun(double jd, struct object_details *details) {
-	ln_get_solar_equ_coords(jd, &details->equ);
+void object_pos(const struct object *o, double jd, struct object_details *details)
+{
+	o->equ_coords(jd, &details->equ);
 
-	details->distance = ln_get_earth_solar_dist(jd);
-	details->diameter = ln_get_solar_sdiam(jd);
+	details->distance = o->earth_dist(jd);
+	details->diameter = o->sdiam(jd);
 }
 
-void object_pos_moon(double jd, struct object_details *details) {
-	ln_get_lunar_equ_coords(jd, &details->equ);
-
-	details->distance = ln_get_lunar_earth_dist(jd) / AU_METERS;
-	details->diameter = ln_get_lunar_sdiam(jd);
-}
-
-void object_pos_mars(double jd, struct object_details *details) {
-	ln_get_mars_equ_coords(jd, &details->equ);
-
-	details->distance = ln_get_mars_earth_dist(jd);
-	details->diameter = ln_get_mars_sdiam(jd);
-}
-
-void object_pos_neptune(double jd, struct object_details *details) {
-	ln_get_neptune_equ_coords(jd, &details->equ);
-
-	details->distance = ln_get_neptune_earth_dist(jd);
-	details->diameter = ln_get_neptune_sdiam(jd);
-}
-
-void object_pos_jupiter(double jd, struct object_details *details) {
-	ln_get_jupiter_equ_coords(jd, &details->equ);
-
-	details->distance = ln_get_jupiter_earth_dist(jd);
-	details->diameter = ln_get_jupiter_equ_sdiam(jd);
-}
-
-void object_pos_mercury(double jd, struct object_details *details) {
-	ln_get_mercury_equ_coords(jd, &details->equ);
-
-	details->distance = ln_get_mercury_earth_dist(jd);
-	details->diameter = ln_get_mercury_sdiam(jd);
-}
-
-void object_pos_uranus(double jd, struct object_details *details) {
-	ln_get_uranus_equ_coords(jd, &details->equ);
-
-	details->distance = ln_get_uranus_earth_dist(jd);
-	details->diameter = ln_get_uranus_sdiam(jd);
-}
-
-void object_pos_saturn(double jd, struct object_details *details) {
-	ln_get_saturn_equ_coords(jd, &details->equ);
-
-	details->distance = ln_get_saturn_earth_dist(jd);
-	details->diameter = ln_get_saturn_equ_sdiam(jd);
-}
-
-void object_pos_venus(double jd, struct object_details *details) {
-	ln_get_venus_equ_coords(jd, &details->equ);
-
-	details->distance = ln_get_venus_earth_dist(jd);
-	details->diameter = ln_get_venus_sdiam(jd);
-}
-
-void object_pos_pluto(double jd, struct object_details *details) {
-	ln_get_pluto_equ_coords(jd, &details->equ);
-
-	details->distance = ln_get_pluto_earth_dist(jd);
-	details->diameter = ln_get_pluto_sdiam(jd);
-}
+int object_rst(const struct object *o, double jd, double horizon, struct ln_lnlat_posn *obs, struct ln_rst_time *rst)
+{
+	if (o->sdiam == ln_get_solar_sdiam)
+		return ln_get_solar_rst_horizon(jd, obs, horizon, rst); /* special case */
+	else
+		return o->rst(jd, obs, rst);
+}
\ No newline at end of file
diff --git a/src/objects.h b/src/objects.h
index 832b06b..a593a1c 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -30,22 +30,7 @@
 
 #include <stdbool.h>
 
-#define AU_METERS 149597870.7
-#define OBJECTS 10
-
-enum object {
-	OBJECT_INVALID,
-	OBJECT_SUN,
-	OBJECT_MOON,
-	OBJECT_MARS,
-	OBJECT_NEPTUNE,
-	OBJECT_JUPITER,
-	OBJECT_MERCURY,
-	OBJECT_URANUS,
-	OBJECT_SATURN,
-	OBJECT_VENUS,
-	OBJECT_PLUTO
-};
+struct object;
 
 struct object_details {
 	double jd;			/* julian date of observation */
@@ -62,21 +47,10 @@ struct object_details {
 	const char *azidir;		/* direction of azimuth - like N,S,W,E,NSW,.. */
 };
 
-enum object object_from_name(const char *name);
-const char * object_to_name(enum object obj);
+const struct object * object_lookup(const char *name);
+const char * object_name(const struct object *o);
 
-void object_pos(enum object obj, double jd, struct object_details *details);
-int object_rst(enum object obj, double jd, double horizon, struct ln_lnlat_posn *obs, struct ln_rst_time *rst);
-
-void object_pos_sun(double jd, struct object_details *details);
-void object_pos_moon(double jd, struct object_details *details);
-void object_pos_mars(double jd, struct object_details *details);
-void object_pos_neptune(double jd, struct object_details *details);
-void object_pos_jupiter(double jd, struct object_details *details);
-void object_pos_mercury(double jd, struct object_details *details);
-void object_pos_uranus(double jd, struct object_details *details);
-void object_pos_saturn(double jd, struct object_details *details);
-void object_pos_venus(double jd, struct object_details *details);
-void object_pos_pluto(double jd, struct object_details *details);
+void object_pos(const struct object *o, double jd, struct object_details *details);
+int object_rst(const struct object *o, double jd, double horizon, struct ln_lnlat_posn *obs, struct ln_rst_time *rst);
 
 #endif /* _OBJECTS_H_ */