function NmF2Background_GUVI3;
if nargin<1,f=1.0;end;
%%% circle
Lat=[50 60 70 80];   %%%%% to set Latitude circle to show
rho=90-Lat;
theta=-pi:pi/100:pi;
t0=pi/4;
for I=1:length(rho),
    hold on;
    R=ones(1,length(theta))*rho(I);
    if (Lat(I)==50)
        h=polar(theta,R,'w-');   set(h,'LineWidth',1.0); 
    else
	h=polar(theta,R,'w-');   set(h,'LineWidth',0.5);
    end;
   % if Lat(I)==55,   h=polar(theta,R,'k');   set(h,'LineWidth',1.5);    end;
   L0=rho(I);
  x=L0*cos(t0); y=L0*sin(t0);
  %if mod(Lat(I),20)==0,
  %text(x+0.03*x,y-0.05*y,[num2str(Lat(I))],'FontName','Times','FontSize',10,'color','r');
  %end;
end;  
hold on;
Rmax=max(rho);Rmin=min(rho);
%hp=plot([-Rmax Rmax],[0 0],'k:');set(hp,'LineWidth',1.0);
%%% LTime line
theta=-pi:pi/2:pi-0.3;   %%%%%%% to set theta/MLT to show
for I=1:length(theta),
     hold on;
    R=0:0.1:Rmax;
    Theta=ones(1,length(R))*theta(I);
       hp=polar(Theta,R,'c:');    set(h,'LineWidth',0.5);
    lth=(Theta(1)+2*pi+pi/2)/pi*180*24/360;
    if lth>=24,lth=lth-24;end;
    Rmax=rho(Lat==min(Lat));
    x=Rmax*cos(theta(I));y=Rmax*sin(theta(I));
    X=x;Y=y;gap=5;
    if x<0,X=x-gap;end;
    if x>0,X=x+2;end;
    if abs(x)<1e-5&y<0,Y=y-2;X=X-2;end;
    if abs(x)<1e-5&y>0,Y=y+2;X=X-2;end;
     % if (I==1|I==length(theta))&cnt>1,continue;end;
%    text(X,Y,[num2str(lth)],'FontName','Times','FontSize',8,'color','k');
%    text(X,Y,[num2str(lth)],'FontName','Times','FontSize',12,'color','k');
     text(X-0.14*X,Y-0.15*Y,[num2str(lth)],'FontName','Times','FontSize',12,'color','k');
  end;
