PRO STEPHEM2,yr,mo,day,ut,lat,lon,nstars,desig,az,za,mag,vis
ut = ut/(3600.*24.)
jday = 0.
jday = JULDAY(mo, day, yr)
lsidt = LMST(jday, ut, lon)
rdybsc4, n,desig,rtasc,dec,mag
rtasc = rtasc*!DTOR
dec = dec * !DTOR
lat = lat * !DTOR
lsidt = lsidt*2*!PI
hangle = lsidt - rtasc
sinalt = SIN(dec)*SIN(lat) + COS(hangle)*COS(dec)*COS(lat)
za = ACOS(sinalt)
sinaz = -COS(dec)*SIN(hangle)/SIN(za)
cosaz = (SIN(dec) - sinalt*sin(lat))/(SIN(za)*COS(lat))
az = ATAN(sinaz, cosaz)
vis = WHERE(sinalt GT 0.3)
nstars = N_ELEMENTS(vis)
az = az*!RADEG
za = za*!RADEG
lat = lat * !RADEG
RETURN
END