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use crate::rfam::*;
use crate::vector_matrix::angle_ops::anpm::*;
use crate::utils::*;
/// Nutation, IAU 1980 model.
///
/// Given:
/// * date1,date2 TT as a 2-part Julian Date (Note 1)
///
/// Returned:
/// * dpsi nutation in longitude (radians)
/// * deps nutation in obliquity (radians)
///
/// # Notes:
///
/// 1) The TT date date1+date2 is a Julian Date, apportioned in any
/// convenient way between the two arguments. For example,
/// JD(TT)=2450123.7 could be expressed in any of these ways,
/// among others:
///
/// | date1 | date2 | |
/// |-------------|--------------|----------------------|
/// |2450123.7 | 0.0 | (JD method) |
/// |2451545.0 | -1421.3 | (J2000 method) |
/// |2400000.5 | 50123.2 | (MJD method) |
/// |2450123.5 | 0.2 | (date & time method) |
///
/// The JD method is the most natural and convenient to use in
/// cases where the loss of several decimal digits of resolution
/// is acceptable. The J2000 method is best matched to the way
/// the argument is handled internally and will deliver the
/// optimum resolution. The MJD method and the date & time methods
/// are both good compromises between resolution and convenience.
///
/// 2) The nutation components are with respect to the ecliptic of
/// date.
///
/// # Called:
/// * anpm normalize angle into range +/- pi
///
/// # Reference:
/// * Explanatory Supplement to the Astronomical Almanac,
/// P. Kenneth Seidelmann (ed), University Science Books (1992),
/// Section 3.222 (p111).
///
/// This revision: 2021 May 11
pub fn nut80(date1: f64, date2: f64, dpsi: &mut f64, deps: &mut f64)
{
// Units of 0.1 milliarcsecond to radians
const U2R: f64 = URSA_DAS2R / 1e4;
// ------------------------------------------------
// Table of multiples of arguments and coefficients
// ------------------------------------------------
// The units for the sine and cosine coefficients are 0.1 mas and
// the same per Julian century
struct Xls {
nl: i32, nlp: i32, nf: i32, nd: i32, nom: i32, /* coefficients of l,l',F,D,Om */
sp: f64, spt: f64, /* longitude sine, 1 and t coefficients */
ce: f64, cet: f64 /* obliquity cosine, 1 and t coefficients */
}
impl Xls {
pub const fn new(nl: i32,nlp: i32,nf: i32,nd: i32,nom: i32,sp: f64, spt: f64,ce: f64,cet: f64)->Self{
Xls { nl: nl, nlp: nlp, nf: nf, nd: nd, nom: nom, sp: sp, spt: spt, ce: ce, cet: cet }
}
}
const X:[Xls; 106] = [
// 1-10
Xls::new(0, 0, 0, 0, 1, -171996.0, -174.2, 92025.0, 8.9 ),
Xls::new( 0, 0, 0, 0, 2, 2062.0, 0.2, -895.0, 0.5 ),
Xls::new( -2, 0, 2, 0, 1, 46.0, 0.0, -24.0, 0.0 ),
Xls::new( 2, 0, -2, 0, 0, 11.0, 0.0, 0.0, 0.0 ),
Xls::new( -2, 0, 2, 0, 2, -3.0, 0.0, 1.0, 0.0 ),
Xls::new( 1, -1, 0, -1, 0, -3.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, -2, 2, -2, 1, -2.0, 0.0, 1.0, 0.0 ),
Xls::new( 2, 0, -2, 0, 1, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 0, 2, -2, 2, -13187.0, -1.6, 5736.0, -3.1 ),
Xls::new( 0, 1, 0, 0, 0, 1426.0, -3.4, 54.0, -0.1 ),
// 11-20
Xls::new( 0, 1, 2, -2, 2, -517.0, 1.2, 224.0, -0.6 ),
Xls::new( 0, -1, 2, -2, 2, 217.0, -0.5, -95.0, 0.3 ),
Xls::new( 0, 0, 2, -2, 1, 129.0, 0.1, -70.0, 0.0 ),
Xls::new( 2, 0, 0, -2, 0, 48.0, 0.0, 1.0, 0.0 ),
Xls::new( 0, 0, 2, -2, 0, -22.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 2, 0, 0, 0, 17.0, -0.1, 0.0, 0.0 ),
Xls::new( 0, 1, 0, 0, 1, -15.0, 0.0, 9.0, 0.0 ),
Xls::new( 0, 2, 2, -2, 2, -16.0, 0.1, 7.0, 0.0 ),
Xls::new( 0, -1, 0, 0, 1, -12.0, 0.0, 6.0, 0.0 ),
Xls::new( -2, 0, 0, 2, 1, -6.0, 0.0, 3.0, 0.0 ),
// 21-30
Xls::new( 0, -1, 2, -2, 1, -5.0, 0.0, 3.0, 0.0 ),
Xls::new( 2, 0, 0, -2, 1, 4.0, 0.0, -2.0, 0.0 ),
Xls::new( 0, 1, 2, -2, 1, 4.0, 0.0, -2.0, 0.0 ),
Xls::new( 1, 0, 0, -1, 0, -4.0, 0.0, 0.0, 0.0 ),
Xls::new( 2, 1, 0, -2, 0, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 0, -2, 2, 1, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 1, -2, 2, 0, -1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 1, 0, 0, 2, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( -1, 0, 0, 1, 1, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 1, 2, -2, 0, -1.0, 0.0, 0.0, 0.0 ),
// 31-40
Xls::new( 0, 0, 2, 0, 2, -2274.0, -0.2, 977.0, -0.5 ),
Xls::new( 1, 0, 0, 0, 0, 712.0, 0.1, -7.0, 0.0 ),
Xls::new( 0, 0, 2, 0, 1, -386.0, -0.4, 200.0, 0.0 ),
Xls::new( 1, 0, 2, 0, 2, -301.0, 0.0, 129.0, -0.1 ),
Xls::new( 1, 0, 0, -2, 0, -158.0, 0.0, -1.0, 0.0 ),
Xls::new( -1, 0, 2, 0, 2, 123.0, 0.0, -53.0, 0.0 ),
Xls::new( 0, 0, 0, 2, 0, 63.0, 0.0, -2.0, 0.0 ),
Xls::new( 1, 0, 0, 0, 1, 63.0, 0.1, -33.0, 0.0 ),
Xls::new( -1, 0, 0, 0, 1, -58.0, -0.1, 32.0, 0.0 ),
Xls::new( -1, 0, 2, 2, 2, -59.0, 0.0, 26.0, 0.0 ),
// 41-50
Xls::new( 1, 0, 2, 0, 1, -51.0, 0.0, 27.0, 0.0 ),
Xls::new( 0, 0, 2, 2, 2, -38.0, 0.0, 16.0, 0.0 ),
Xls::new( 2, 0, 0, 0, 0, 29.0, 0.0, -1.0, 0.0 ),
Xls::new( 1, 0, 2, -2, 2, 29.0, 0.0, -12.0, 0.0 ),
Xls::new( 2, 0, 2, 0, 2, -31.0, 0.0, 13.0, 0.0 ),
Xls::new( 0, 0, 2, 0, 0, 26.0, 0.0, -1.0, 0.0 ),
Xls::new( -1, 0, 2, 0, 1, 21.0, 0.0, -10.0, 0.0 ),
Xls::new( -1, 0, 0, 2, 1, 16.0, 0.0, -8.0, 0.0 ),
Xls::new( 1, 0, 0, -2, 1, -13.0, 0.0, 7.0, 0.0 ),
Xls::new( -1, 0, 2, 2, 1, -10.0, 0.0, 5.0, 0.0 ),
// 51-60
Xls::new( 1, 1, 0, -2, 0, -7.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 1, 2, 0, 2, 7.0, 0.0, -3.0, 0.0 ),
Xls::new( 0, -1, 2, 0, 2, -7.0, 0.0, 3.0, 0.0 ),
Xls::new( 1, 0, 2, 2, 2, -8.0, 0.0, 3.0, 0.0 ),
Xls::new( 1, 0, 0, 2, 0, 6.0, 0.0, 0.0, 0.0 ),
Xls::new( 2, 0, 2, -2, 2, 6.0, 0.0, -3.0, 0.0 ),
Xls::new( 0, 0, 0, 2, 1, -6.0, 0.0, 3.0, 0.0 ),
Xls::new( 0, 0, 2, 2, 1, -7.0, 0.0, 3.0, 0.0 ),
Xls::new( 1, 0, 2, -2, 1, 6.0, 0.0, -3.0, 0.0 ),
Xls::new( 0, 0, 0, -2, 1, -5.0, 0.0, 3.0, 0.0 ),
// 61-70
Xls::new( 1, -1, 0, 0, 0, 5.0, 0.0, 0.0, 0.0 ),
Xls::new( 2, 0, 2, 0, 1, -5.0, 0.0, 3.0, 0.0 ),
Xls::new( 0, 1, 0, -2, 0, -4.0, 0.0, 0.0, 0.0 ),
Xls::new( 1, 0, -2, 0, 0, 4.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 0, 0, 1, 0, -4.0, 0.0, 0.0, 0.0 ),
Xls::new( 1, 1, 0, 0, 0, -3.0, 0.0, 0.0, 0.0 ),
Xls::new( 1, 0, 2, 0, 0, 3.0, 0.0, 0.0, 0.0 ),
Xls::new( 1, -1, 2, 0, 2, -3.0, 0.0, 1.0, 0.0 ),
Xls::new( -1, -1, 2, 2, 2, -3.0, 0.0, 1.0, 0.0 ),
Xls::new( -2, 0, 0, 0, 1, -2.0, 0.0, 1.0, 0.0 ),
// 71-80
Xls::new( 3, 0, 2, 0, 2, -3.0, 0.0, 1.0, 0.0 ),
Xls::new( 0, -1, 2, 2, 2, -3.0, 0.0, 1.0, 0.0 ),
Xls::new( 1, 1, 2, 0, 2, 2.0, 0.0, -1.0, 0.0 ),
Xls::new( -1, 0, 2, -2, 1, -2.0, 0.0, 1.0, 0.0 ),
Xls::new( 2, 0, 0, 0, 1, 2.0, 0.0, -1.0, 0.0 ),
Xls::new( 1, 0, 0, 0, 2, -2.0, 0.0, 1.0, 0.0 ),
Xls::new( 3, 0, 0, 0, 0, 2.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 0, 2, 1, 2, 2.0, 0.0, -1.0, 0.0 ),
Xls::new( -1, 0, 0, 0, 2, 1.0, 0.0, -1.0, 0.0 ),
Xls::new( 1, 0, 0, -4, 0, -1.0, 0.0, 0.0, 0.0 ),
// 81-90
Xls::new( -2, 0, 2, 2, 2, 1.0, 0.0, -1.0, 0.0 ),
Xls::new( -1, 0, 2, 4, 2, -2.0, 0.0, 1.0, 0.0 ),
Xls::new( 2, 0, 0, -4, 0, -1.0, 0.0, 0.0, 0.0 ),
Xls::new( 1, 1, 2, -2, 2, 1.0, 0.0, -1.0, 0.0 ),
Xls::new( 1, 0, 2, 2, 1, -1.0, 0.0, 1.0, 0.0 ),
Xls::new( -2, 0, 2, 4, 2, -1.0, 0.0, 1.0, 0.0 ),
Xls::new( -1, 0, 4, 0, 2, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( 1, -1, 0, -2, 0, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( 2, 0, 2, -2, 1, 1.0, 0.0, -1.0, 0.0 ),
Xls::new( 2, 0, 2, 2, 2, -1.0, 0.0, 0.0, 0.0 ),
// 91-100
Xls::new( 1, 0, 0, 2, 1, -1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 0, 4, -2, 2, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( 3, 0, 2, -2, 2, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( 1, 0, 2, -2, 0, -1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 1, 2, 0, 1, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( -1, -1, 0, 2, 1, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 0, -2, 0, 1, -1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 0, 2, -1, 2, -1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 1, 0, 2, 0, -1.0, 0.0, 0.0, 0.0 ),
Xls::new( 1, 0, -2, -2, 0, -1.0, 0.0, 0.0, 0.0 ),
// 101-106
Xls::new( 0, -1, 2, 0, 1, -1.0, 0.0, 0.0, 0.0 ),
Xls::new( 1, 1, 0, -2, 1, -1.0, 0.0, 0.0, 0.0 ),
Xls::new( 1, 0, -2, 2, 0, -1.0, 0.0, 0.0, 0.0 ),
Xls::new( 2, 0, 0, 2, 0, 1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 0, 2, 4, 2, -1.0, 0.0, 0.0, 0.0 ),
Xls::new( 0, 1, 0, 1, 0, 1.0, 0.0, 0.0, 0.0 )
];
// ------------------------------------------------------------------
// Interval between fundamental epoch J2000.0 and given date (JC).
let t = ((date1 - URSA_DJ00) + date2) / URSA_DJC;
// ---------------------
// Fundamental arguments
// ---------------------
// Mean longitude of Moon minus mean longitude of Moon's perigee.
let el = anpm(
(485866.733 + (715922.633 + (31.310 + 0.064 * t) * t) * t)
* URSA_DAS2R + fmod(1325.0 * t, 1.0) * URSA_D2PI);
// Mean longitude of Sun minus mean longitude of Sun's perigee.
let elp = anpm(
(1287099.804 + (1292581.224 + (-0.577 - 0.012 * t) * t) * t)
* URSA_DAS2R + fmod(99.0 * t, 1.0) * URSA_D2PI);
// Mean longitude of Moon minus mean longitude of Moon's node.
let f = anpm(
(335778.877 + (295263.137 + (-13.257 + 0.011 * t) * t) * t)
* URSA_DAS2R + fmod(1342.0 * t, 1.0) * URSA_D2PI);
// Mean elongation of Moon from Sun.
let d = anpm(
(1072261.307 + (1105601.328 + (-6.891 + 0.019 * t) * t) * t)
* URSA_DAS2R + fmod(1236.0 * t, 1.0) * URSA_D2PI);
// Longitude of the mean ascending node of the lunar orbit on the
// ecliptic, measured from the mean equinox of date.
let om = anpm(
(450160.280 + (-482890.539 + (7.455 + 0.008 * t) * t) * t)
* URSA_DAS2R + fmod(-5.0 * t, 1.0) * URSA_D2PI);
// ---------------
// Nutation series
// ---------------
// Initialize nutation components.
let mut dp = 0.0;
let mut de = 0.0;
// Sum the nutation terms, ending with the biggest.
for x_j in X.iter() {
// Form argument for current term.
let arg = x_j.nl as f64 * el
+ x_j.nlp as f64 * elp
+ x_j.nf as f64 * f
+ x_j.nd as f64 * d
+ x_j.nom as f64 * om;
// Accumulate current nutation term.
let s = x_j.sp + x_j.spt * t;
let c = x_j.ce + x_j.cet * t;
if s != 0.0 {dp += s * sin(arg)};
if c != 0.0 {de += c * cos(arg)};
}
// Convert results from 0.1 mas units to radians.
*dpsi = dp * U2R;
*deps = de * U2R;
// Finished.
}