def ajd_to_elos(ajd)
almanac_math = AlmanacMath.new
t = (ajd - 2451545.0) / 36525.0
elos = 280.4659 + 36000.7695 * t
elos = elos + 1.9147 * almanac_math.degree_cos( 35999.05 * t + 267.52)
elos = elos - 0.0048 * t * almanac_math.degree_cos( 35999.05 * t + 267.52)
elos = elos + 0.0200 * almanac_math.degree_cos( 71998.1 * t + 265.1 )
elos = elos + 0.0020 * almanac_math.degree_cos( 32964.0 * t + 158.0 )
elos = elos + 0.0018 * almanac_math.degree_cos( 19.0 * t + 159.0 )
elos = elos + 0.0018 * almanac_math.degree_cos(445267.0 * t + 208.0 )
elos = elos + 0.0015 * almanac_math.degree_cos( 45038.0 * t + 254.0 )
elos = elos + 0.0013 * almanac_math.degree_cos( 22519.0 * t + 352.0 )
elos = elos + 0.0007 * almanac_math.degree_cos( 65929.0 * t + 45.0 )
elos = elos + 0.0007 * almanac_math.degree_cos( 3035.0 * t + 110.0 )
elos = elos + 0.0007 * almanac_math.degree_cos( 9038.0 * t + 64.0 )
elos = elos + 0.0006 * almanac_math.degree_cos( 33718.0 * t + 316.0 )
elos = elos + 0.0005 * almanac_math.degree_cos( 115.0 * t + 118.0 )
elos = elos + 0.0005 * almanac_math.degree_cos( 2281.0 * t + 221.0 )
elos = elos + 0.0004 * almanac_math.degree_cos( 29930.0 * t + 48.0 )
elos = elos + 0.0004 * almanac_math.degree_cos( 31557.0 * t + 161.0 )
elos = almanac_math.put_between_from_0_to_360(elos)
return elos
end