diff --git a/dec_time.m b/dec_time.m
new file mode 100644
--- /dev/null
+++ b/dec_time.m
@@ -0,0 +1,28 @@
+%======================================================================
+%                    D E C _ T I M E . M 
+%                    doc: Thu Mar  1 18:16:50 2012
+%                    dlm: Thu Mar  1 18:18:15 2012
+%                    (c) 2012 A.M. Thurnherr
+%                    uE-Info: 15 0 NIL 0 0 72 0 2 4 NIL ofnI
+%======================================================================
+% 
+%	dt = dec_time(time[,epoch])
+%
+% 	make ATNS dn field from matlab numeric time
+%
+% HISTORY:
+%	Mar  1, 2012: - created
+
+function dt=dec_time(time,varargin)
+
+if nargin==2
+	dt = time - datenum(varargin{1},1,1) + 1;
+elseif nargin==1
+	dv = datevec(time);
+	dt = dec_time(time,dv(1));
+else
+	disp('dt=dec_time(time[,epoch])');
+	error
+end
+
+