diff --git a/GUI/xephem/datamenu.c b/GUI/xephem/datamenu.c
index 7f5b148..23b1c86 100644
--- a/GUI/xephem/datamenu.c
+++ b/GUI/xephem/datamenu.c
@@ -109,7 +109,7 @@ static ColHdr col[] = {
     {MISC_COL,	"SnLght",  "Light travel time from Sun"},
     {MISC_COL,	"Uranom",  "Volume and page number in Uranometria"},
     {MISC_COL,	"Uran2k",  "Volume and page number in Uranometria 2000"},
-    {MISC_COL,	"MillSA",  "Volume and page number in Millenium Star Atlas"},
+    {MISC_COL,	"MillSA",  "Volume and page number in Millennium Star Atlas"},
 
     {RISET_COL,	"RisTm",   "Rise time, today"},
     {RISET_COL,	"RisAz",   "Rise azimuth, today"},
diff --git a/GUI/xephem/help/xephem.html b/GUI/xephem/help/xephem.html
index ec5b04d..2c397c9 100644
--- a/GUI/xephem/help/xephem.html
+++ b/GUI/xephem/help/xephem.html
@@ -1753,7 +1753,7 @@ number of object's location in the new Uranometria 2000 edition.</li>
 </ul>
 <ul>
   <li><span style="font-weight: bold;">MillSA</span> Volume and Page
-number of object's location in the Millenium Star Atlas, published
+number of object's location in the Millennium Star Atlas, published
 by Sky Publishing Corp.</li>
 </ul>
 Section two controls information related to rising, transitting, and
diff --git a/GUI/xephem/imregmenu.c b/GUI/xephem/imregmenu.c
index b0e9e26..a7c647b 100644
--- a/GUI/xephem/imregmenu.c
+++ b/GUI/xephem/imregmenu.c
@@ -229,7 +229,7 @@ ir_create()
 	s2_w = XmCreateToggleButton (irshell_w, "S1TB", args, n);
 	XtAddCallback (s2_w, XmNvalueChangedCallback, reg_cb, NULL);
 	set_xmstring (s2_w, XmNlabelString,
-		    "Image to be registed is loaded, now click same 2 stars");
+		    "Image to be registered is loaded, now click same 2 stars");
 	XtManageChild (s2_w);
 
 	/* labels for second set of reference stars */
diff --git a/GUI/xephem/skylist.c b/GUI/xephem/skylist.c
index cdfcc73..2c04e02 100644
--- a/GUI/xephem/skylist.c
+++ b/GUI/xephem/skylist.c
@@ -98,7 +98,7 @@ typedef struct {
     char *desc;			/* description */
     char ura[ATLASLEN];		/* Uranometria page number */
     char u2k[ATLASLEN];		/* Uranometria 200 page number */
-    char msa[ATLASLEN];		/* Millenium Star Atlas page number */
+    char msa[ATLASLEN];		/* Millennium Star Atlas page number */
 } ObjInfo;
 
 /* handy "no rise/set" test */
@@ -139,7 +139,7 @@ static SortInfo sinfo[] = {
 
     {"Urano",  "Uranometria",      sort_ura},
     {"Uran2k", "Uranom 2000",      sort_u2k},
-    {"MillSA", "Millenium",        sort_msa},
+    {"MillSA", "Millennium",       sort_msa},
     {"RisTm",  "Rise time",        sort_risetm},
     {"RisAz",  "Rise azimuth",     sort_riseaz},
     {"TrnTm",  "Transit time",     sort_trantm},