Sofa

This project is a basic astronomy calculation library implemented purely in Rust, based on the official Standards of Fundamental Astronomy (SOFA) by the International Astronomical Union.

Refer to the documentation for detail.

License

sofars follows the MIT license.

In addition to the MIT license, any use of this module must also comply with the SOFA license and terms of use, which are detailed in the license file.

In particular (but not limited to), any published work or commercial product that includes results obtained using sofa-rs should acknowledge the use of algorithms provided by the SOFA ANSIC source code to obtain these results.

lib.rs:

Sofa

This project is a basic astronomy calculation library implemented purely in Rust, based on the official Standards of Fundamental Astronomy (SOFA) by the International Astronomical Union.

Refer to the documentation for detail.

License

sofa-rs follows the MIT license.

In addition to the MIT license, any use of this module must also comply with the SOFA license and terms of use, which are detailed in the license file.

In particular (but not limited to), any published work or commercial product that includes results obtained using sofa-rs should acknowledge the use of algorithms provided by the SOFA ANSIC source code to obtain these results.

Example

use sofars::astro::*;
use sofars::consts::*;
use sofars::eph::epv00;
use sofars::pnp::bpn2xy;
use sofars::pnp::pnm00a;
use sofars::pnp::s06;
use sofars::ts; 
use sofars::vm;

use std::thread;

fn reprd(s: &str, ra: f64, dc: f64) {
    let mut pm: char;
    let mut i: [i32; 4] = [0; 4];

    print!("{:25}", s);
    (pm, i) = vm::a2tf(7, ra);
    if pm == '+' {
        pm = ' ';
    }
    print!("{}{:02} {:02} {:02}.{:07} ", pm, i[0], i[1], i[2], i[3]);
    (pm, i) = vm::a2af(6, dc);
    println!("{}{:02} {:02} {:02}.{:06}", pm, i[0], i[1], i[2], i[3]);
}

fn example() {

    /* Site longitude, latitude (radians) and height above the geoid (m). */
    let elong = vm::af2a('-', 5, 41, 54.2).unwrap();
    let phi = vm::af2a('-', 15, 57, 42.8).unwrap();
    let hm = 625.0;

    /* Ambient pressure (HPa), temperature (C) and rel. humidity (frac). */
    let phpa = 952.0;
    let tc = 18.5;
    let rh = 0.83;

    /* Effective color (microns). */
    let wl = 0.55;

    /* UTC date */
    let (utc1, utc2) = match ts::dtf2d("UTC", 2013, 4, 2, 23, 15, 43.55) {
        Ok(t) => t,
        Err(_) => return (),
    };

    /* TT date */
    let (tai1, tai2) = match ts::utctai(utc1, utc2) {
        Ok(t) => t,
        Err(_) => return (),
    };
    let (tt1, tt2) = match ts::taitt(tai1, tai2) {
        Ok(t) => t,
        Err(_) => return (),
    };

    /* EOPs: polar motion in radians, UT1-UTC in seconds. */
    let xp = 50.995e-3 * DAS2R;
    let yp = 376.723e-3 * DAS2R;
    let dut1 = 155.0675e-3;

    /* Corrections to IAU 2000A CIP (radians). */
    let dx = 0.269e-3 * DAS2R;
    let dy = -0.274e-3 * DAS2R;

    /* Star ICRS RA,Dec (radians). */
    let rc = match vm::tf2a(' ', 14, 34, 16.81183) {
        Ok(rc) => rc,
        Err(_) => return (),
    };
    let dc = match vm::af2a('-', 12, 31, 10.3965) {
        Ok(dc) => dc,
        Err(_) => return (),
    };
    reprd("ICRS, epoch J2000.0:", rc, dc);
    /* Annual proper motion: RA/Dec derivatives, epoch J2000.0. */
    let pr = (-354.45e-3 * DAS2R).atan2(dc.cos());
    let pd = 595.35e-3 * DAS2R;
  
    /* Parallax (arcsec) and recession speed (km/s). */
    let px = 164.99e-3;
    let rv = 0.0;
 

    /* ICRS catalog to astrometric place... */
    let (rca, dca) = atcc13(rc, dc, pr, pd, px, rv, tt1, tt2);
    reprd("catalog -> astrometric:", rca, dca);

    /* ...then to CIRS (geocentric observer) */
    let (ri, di, eo) = atci13(rca, dca, 0.0, 0.0, 0.0, 0.0, tt1, tt2);
    reprd("astrometric -> CIRS:", ri, di);

    /* ICRS catalog directly to CIRS (geocentric observer). */
    let (ri, di, eo) = atci13(rc, dc, pr, pd, px, rv, tt1, tt2);
    reprd("catalog -> CIRS:", ri, di);

    /* Apparent place */
    let ra = vm::anp(ri - eo);
    let da = di;
    reprd("geocentric apparent:", ra, da);

    /* CIRS to topocentric. */
    let (aot, zot, hot, dot, rot) = atio13(ri, di, utc1, utc2, dut1, elong, phi, hm, xp, yp, 0.0, 0.0, 0.0, 0.0).unwrap();
    reprd("CIRS -> topocentric:", rot, dot);

    /* CIRS to observed. */
    let (aob, zob, hob, dob, rob)= atio13(ri, di, utc1, utc2, dut1, elong, phi, hm, xp, yp, phpa, tc, rh, wl).unwrap();
    reprd("CIRS -> observed:", rob, dob);

    /* ICRS to observed. */
    let (aob, zob, hob, dob, rob, eo) = atco13(rc, dc, pr, pd, px, rv, utc1, utc2, dut1, elong, phi, hm, xp, yp, phpa, tc, rh, wl).unwrap();
    reprd("ICRS -> observed:", rob, dob);

    /* ICRS to CIRS using some user-supplied parameters. */
    /* SOFA heliocentric Earth ephemeris. */
    let (pvh, pvb) = &mut epv00(tt1, tt2).unwrap();

    /* JPL DE405 barycentric Earth ephemeris. */
    pvb[0][0] = -0.9741704366519668;
    pvb[0][1] = -0.2115201000882231;
    pvb[0][2] = -0.0917583114068277;
    pvb[1][0] = 0.0036436589347388;
    pvb[1][1] = -0.0154287318503146;
    pvb[1][2] = -0.0066892203821059;

    /* IAU 2000 CIP */
    let r = &mut [[0.0; 3]; 3];
    pnm00a(tt1, tt2, r);
    let (mut x, mut y) = bpn2xy(r);

    /* Apply IERS corrections */
    x += dx;
    y += dy;

    /* SOFA CIO locator. */
    let s = s06(tt1, tt2, x, y);

    let astrom = &mut IauAstrom::default();
    /* Populate the context. */
    apci(tt1, tt2, &pvb, &pvh[0], x, y, s, astrom);

    /* Carry out the transformation and report the results. */
    let (ri, di) = atciq(rc, dc, pr, pd, px, rv, astrom);
    reprd("ICRS -> CIRS (JPL, IERS):", ri, di);
    
    /* The same but with Saturn then Jupiter then Sun light deflection. */
    let mut b = [
        IauLdBody::new(0.00028574, 3e-10, [
            [-7.8101442680818964, -5.6095668114887358, -1.9807981923749924],
            [0.0030723248971152, -0.0040699547707598, -0.0018133584165345]
        ]),
        IauLdBody::new(0.00095435, 3e-9, [
            [0.7380987962351833, 4.6365869247538951, 1.9693136030111202],
            [-0.0075581692172088, 0.0012691372216750, 0.0007279990012801]
        ]),
        IauLdBody::new(1.0, 6e-6, [
            [-0.0007121743770509, -0.0023047830339257, -0.0010586596574639],
            [0.0000062923521264, -0.0000003308883872, -0.0000002964866231]
        ])
    ];

    let (ri, di) = atciqn(rc, dc, pr, pd, px, rv, astrom, 3, &b);
    reprd("ICRS -> CIRS (+ planets):", ri, di);

    /* CIRS to ICRS (astrometric). */
    let (rca, dca) = aticqn(ri, di, astrom, 3, &b);
    reprd("CIRS -> astrometric:", rca, dca);
}

// Output: 
//
// ICRS, epoch J2000.0:      14 34 16.8118300 -12 31 10.396500
// catalog -> astrometric:   14 34 16.4960283 -12 31 02.523786
// astrometric -> CIRS:      14 34 20.2370587 -12 34 36.381654
// catalog -> CIRS:          14 34 20.2370587 -12 34 36.381654
// geocentric apparent:      14 35 01.7725802 -12 34 36.381654
// CIRS -> topocentric:      14 34 20.2570287 -12 34 36.141207
// CIRS -> observed:         14 34 16.9649101 -12 34 44.643091
// ICRS -> observed:         14 34 16.9649106 -12 34 44.643094
// ICRS -> CIRS (JPL, IERS): 14 34 20.2370639 -12 34 36.381756
// ICRS -> CIRS (+ planets): 14 34 20.2370658 -12 34 36.381784
// CIRS -> astrometric:      14 34 16.4960283 -12 31 02.523786
//
fn main() {
    let stack_size = 2 * 1024 * 1024;
    let name = String::from("mycal thread");

    let builder = thread::Builder::new().stack_size(stack_size).name(name);

    let handler = builder.spawn(|| {
        example();
    }).unwrap();

    handler.join().unwrap();
}