function plotion(color,lt,type,geo,RE)

if nargin<5
    RE=1.0;
end

if nargin<4
    geo = 'MLT';
end

if nargin<3
    type = 'sat';
end

if nargin<2
    lt=[70,80];
end

if nargin<1
    color = 'k';
end

if(strcmp(type,'sat')==1)
    
tm=0:1:23;

for k=1:length(lt)
    theta=0:1:360;
    x=RE*sin(pi/2-lt(k)/180*pi).*cos(theta/180*pi);
    y=RE*sin(pi/2-lt(k)/180*pi).*sin(theta/180*pi);  
    if(k==1)
        str='-';
    plot(x,y,'LineWidth',1,'LineStyle',str,'color','k')      
    else
        str=':';
    plot(x,y,'LineWidth',1,'LineStyle',str,'color',color)    
    end
    hold on
 end

for p=1:length(tm)
    rr=((RE*sin(pi/2-lt(1)/180*pi))-0.02):0.01:(RE*sin(pi/2-lt(1)/180*pi));
    beta=tm(p)*2*pi/24;
    x=rr.*cos(beta);
    y=rr.*sin(beta);
    plot(x,y,'LineWidth',1,'LineStyle','-','color',color)  
end
 %text(0.51,0.51,'55^o','FontSize',12)
%  text(0.42,0.42,'60^o','FontSize',16,'color','k') ;
%  text(0.3,0.3,'70^o','FontSize',16,'color',color)  ;
%  t1=text(0.7,0.1,'12 MLT','FontSize',16);
%  t2=text(-0.016,0.76,'18','FontSize',16);
box off;
%axis off
end

if(strcmp(type,'polar')==1)
    
    tm=0:1:23;
    
    for k=1:length(lt)
        theta=0:1:360;
%         x=1.02*sin(pi/2-lt(k)/180*pi).*cos(theta/180*pi);
%         y=1.02*sin(pi/2-lt(k)/180*pi).*sin(theta/180*pi);
        
x= RE*(pi/2-lt(k)/180*pi).*cos(theta/180*pi);
y= RE*(pi/2-lt(k)/180*pi).*sin(theta/180*pi);

        if(k==1)
            str='-';
            plot(x,y,'LineWidth',1,'LineStyle',str,'color','k')
        else
            str=':';
            plot(x,y,'LineWidth',1,'LineStyle',str,'color',color)
        end
        hold on
    end
    
    for p=1:length(tm)
        rr=((RE*(pi/2-lt(1)/180*pi))-0.02):0.01:(RE*(pi/2-lt(1)/180*pi));
        beta=tm(p)*2*pi/24;
        x=rr.*cos(beta);
        y=rr.*sin(beta);
        plot(x,y,'LineWidth',1,'LineStyle','-','color',color)
    end
    %text(0.51,0.51,'55^o','FontSize',12)
%     text(0.42,0.42,'60^o','FontSize',16,'color','k') ;
%     text(0.3,0.3,'70^o','FontSize',16,'color',color)  ;
    %  t1=text(0.7,0.1,'12 MLT','FontSize',16);
    %  t2=text(-0.016,0.76,'18','FontSize',16);
    box off;
    %axis off
end

% put on latitude labels
for k=1:1:length(lt)
    if(k==1)
%       t1=text(sin((90-lt(k))*pi/180)*cos(pi/4)*1.1,(90-lt(k))*pi/180*sin(pi/4)*1.1,0,num2str(round(lt(k))),'fontsize',16,'color','k');
    else
        t1=text(sin((90-lt(k))*pi/180)*cos(pi/4)*1.1,sin((90-lt(k))*pi/180)*sin(pi/4)*1.1,0,num2str(lt(k)),'fontsize',16,'color',color);
    end
end
%put on mlt labels
t1=text(sin((90-lt(1))*pi/180)*cos(0*pi)*1.08,sin((90-lt(1))*pi/180)*sin(0*pi)*1.1+0.05,0,['12 ',geo],'fontsize',16,'color','k');
t1=text(sin((90-lt(1))*pi/180)*cos(0.5*pi)*1.1-0.02,sin((90-lt(1))*pi/180)*sin(0.5*pi)*1.15,0,'18','fontsize',16,'color','k');