; main_program ephem_nodes
;
; How many interpolation intervals (nodes) are required
; for a 30-hour period for each planet, such that each interval
; covers no more than 4 arc minutes of the planet's motion?
;
; B. Knapp, 2002-03-20
;
  planet = ['Moon','Mercury','Venus','Sun','Mars', $
            'Jupiter','Saturn','Uranus','Neptune','Pluto']
  degperday = [13.1764, 4.0924, 1.6022, 0.9856, 0.5241, $
                0.0831, 0.0335, 0.0118, 0.0060, 0.0040]
;
  motion = degperday*60.0/1440.0 ; arc minutes per minute
  nodetime = 4.0/motion          ; minutes of time per interval
  nodes = 1800.0/nodetime        ; number of nodes
;
; Round up to the nearest integer divisor of 1800
  inodes = intarr(10)
  for j=0,9 do begin
    n = int(nodes[j])+1
    while 1800 mod n ne 0 do n = n+1
    inodes[j] = n
    print, planet[j], degperday[j], motion[j], nodetime[j], $
      nodes[j], inodes[j], format='(a10, f10.4, f12.6, f10.2, f8.2, i6)'
  endfor
;
  end