function zenithcal
%inpput phe, n,w
h1=findobj(0,'tag','now');
m=findobj(h1,'tag','EditText2');
phe=get(m,'string');
phe=str2num(phe)
h2=findobj(0,'tag','zenith');
t=findobj(h2,'tag','EditText1houre');
wk=get(t,'string');
w=str2num(wk);
h3=findobj(0,'tag','zenith');
tk=findobj(h2,'tag','EditText2day');
nk=get(tk,'string');
n=str2num(nk)
if strcmp(wk,'')|strcmp(nk,'')
msgbox('you should enter both houre and day')
else
del=23.45*sin((360*(n+79+284)/365)*3.14/180);
delrad=del*pi/180;
wdegree=(w-12)*15
wrad=wdegree*(pi/180);
zenith=(180/pi)*acos(sin(delrad)*sin(phe*pi/180)+cos(delrad)*cos(phe*pi/180)*cos(wrad))
msgbox(num2str(zenith),'zenith angle(deg)')
end
