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libuniverse — Missing Functions vs libnova

This file tracks functions present in libnova that are not yet implemented in libuniverse. Grouped by module. Items are ordered roughly by implementation priority (foundational algorithms first).

Legend

  • = not started
  • [~] = partially implemented (notes inline)
  • = done

Calendar / Date Utilities

Status libnova function Description
[~] ln_get_julian_day Implemented as get_julian_day() / Date::to_julian_day()
[~] ln_get_date Implemented as JulianDay::to_calendar_date()
[~] ln_get_day_of_week Implemented as Date::week_day() (1=Mon … 7=Sun vs libnova's 0=Sun)
[ ] ln_get_julian_from_sys Get Julian Day from the local system clock
[ ] ln_get_date_from_sys Get calendar date from the local system clock
[ ] ln_get_julian_from_timet Convert a Unix time_t value to Julian Day
[ ] ln_get_timet_from_julian Convert a Julian Day to Unix time_t
[ ] ln_get_julian_local_date Julian Day from a timezone-aware local date
[ ] ln_get_date_from_mpc Parse an MPC packed date string into a calendar date
[ ] ln_get_julian_from_mpc Parse an MPC packed date string directly to Julian Day

Dynamical Time

Status libnova function Description
[~] ln_get_dynamical_time_diff Implemented as delta_t()
[ ] ln_get_jde Compute Julian Ephemeris Day (JDE = JD + ΔT/86400)

Sidereal Time

Status libnova function Description
[~] ln_get_mean_sidereal_time Implemented as get_mean_sidereal_time_from_date()
[x] ln_get_apparent_sidereal_time Implemented as get_apparent_sidereal_time_from_date() — uses Δψ and true obliquity from nutation

Nutation

Status libnova function Description
[x] ln_get_nutation Nutation in longitude (Δψ) and obliquity (Δε) from JDE — Meeus ch. 22

Aberration

Status libnova function Description
[x] ln_get_equ_aber Implemented as annual_aberration() in aberration.rs — returns (Δα, Δδ) in arcseconds — Meeus ch. 23
[ ] ln_get_ecl_aber Ecliptical coordinates corrected for annual aberration

Precession

Status libnova function Description
[ ] ln_get_equ_prec Precess equatorial coordinates from a given epoch to J2000 — Meeus ch. 21
[ ] ln_get_equ_prec2 Precess equatorial coordinates between two arbitrary epochs
[ ] ln_get_ecl_prec Precess ecliptical coordinates — Meeus ch. 21

Coordinate Transformations

Status libnova function Description
[~] (DMS/HMS conversions) ra_to_deg, deg_to_ra, dec_to_deg, deg_to_dms implemented
[ ] ln_get_hrz_from_equ Equatorial → Horizontal (altitude/azimuth) — Meeus ch. 13
[ ] ln_get_hrz_from_equ_sidereal_time Same, accepting pre-computed mean sidereal time
[ ] ln_get_equ_from_hrz Horizontal → Equatorial
[ ] ln_get_equ_from_ecl Ecliptical → Equatorial — Meeus ch. 13
[ ] ln_get_ecl_from_equ Equatorial → Ecliptical
[ ] ln_get_rect_from_helio Heliocentric → Geocentric rectangular coordinates
[ ] ln_get_ecl_from_rect Rectangular → Ecliptical coordinates
[ ] ln_get_equ_from_gal Galactic → B1950 equatorial coordinates
[ ] ln_get_equ2000_from_gal Galactic → J2000 equatorial coordinates
[ ] ln_get_gal_from_equ B1950 equatorial → Galactic coordinates
[ ] ln_get_gal_from_equ2000 J2000 equatorial → Galactic coordinates

Angular Separation

Status libnova function Description
[ ] ln_get_angular_separation Angular separation between two equatorial positions — Meeus ch. 17
[ ] ln_get_rel_posn_angle Relative position angle between two equatorial positions

Atmospheric Refraction

Status libnova function Description
[ ] ln_get_refraction_adj Altitude correction for atmospheric refraction given pressure & temperature — Meeus ch. 16

Apparent Position of a Star

Status libnova function Description
[ ] ln_get_apparent_posn Full apparent position: proper motion + precession + nutation + aberration

Heliocentric Time

Status libnova function Description
[ ] ln_get_heliocentric_time_diff Barycentric/heliocentric time correction for a given object and date

Lunar (Moon)

Status libnova function Description
[x] ln_get_lunar_equ_coords get_moon_position() returns RA/Dec — full Meeus ch. 47 series
[x] ln_get_lunar_equ_coords_prec Same function — full 60-term Tables 47.A/47.B, verified against Meeus ch. 47 example
[x] ln_get_lunar_ecl_coords Ecliptic longitude/latitude returned by get_moon_position()
[x] ln_get_lunar_earth_dist Distance field in MoonPosition.distance
[ ] ln_get_lunar_geo_posn Rectangular geocentric coordinates of the Moon
[ ] ln_get_lunar_phase Phase angle of the Moon — Meeus ch. 48
[ ] ln_get_lunar_disk Illuminated fraction of the lunar disk
[ ] ln_get_lunar_bright_limb Position angle of the bright limb
[ ] ln_get_lunar_long_asc_node Longitude of the Moon's mean ascending node
[ ] ln_get_lunar_long_perigee Longitude of the Moon's mean perigee
[ ] ln_get_lunar_sdiam Semidiameter of the Moon in arc seconds
[ ] ln_get_lunar_rst Rise, set, and transit times for the Moon

Solar (Sun)

Status libnova function Description
[ ] ln_get_solar_equ_coords Apparent equatorial coordinates of the Sun — Meeus ch. 25/27
[ ] ln_get_solar_ecl_coords Apparent ecliptical coordinates of the Sun
[ ] ln_get_solar_geo_coords Geocentric rectangular coordinates of the Sun (AU)
[ ] ln_get_solar_geom_coords Geometric (high-precision VSOP87) position of the Sun
[ ] ln_get_solar_sdiam Semidiameter of the Sun in arc seconds
[ ] ln_get_solar_rst Rise, set, and transit times for the Sun
[ ] ln_get_solar_rst_horizon Rise/set over a custom horizon elevation

Planets

Each planet needs the same set of functions. libnova covers: Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.

Status Function pattern Description
[ ] get_<planet>_helio_coords Heliocentric coordinates (FK5) — VSOP87
[ ] get_<planet>_equ_coords Equatorial coordinates
[ ] get_<planet>_earth_dist Planet–Earth distance (AU)
[ ] get_<planet>_solar_dist Planet–Sun distance (AU)
[ ] get_<planet>_magnitude Apparent visual magnitude
[ ] get_<planet>_disk Illuminated fraction of the disk
[ ] get_<planet>_phase Phase angle
[ ] get_<planet>_sdiam Semidiameter in arc seconds
[ ] get_<planet>_rst Rise, set, and transit times
[ ] get_<planet>_rect_helio Rectangular heliocentric coordinates (AU)

Planets to implement: Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto

Earth

Status libnova function Description
[ ] ln_get_earth_helio_coords Heliocentric coordinates of Earth (VSOP87)
[ ] ln_get_earth_solar_dist Earth–Sun distance (AU)
[ ] ln_get_earth_rect_helio Rectangular heliocentric coordinates of Earth

Rise, Set, and Transit

Status libnova function Description
[ ] ln_get_object_rst Generic rise/set/transit for any celestial object — Meeus ch. 15
[ ] ln_get_object_next_rst Next rise/set/transit after a given JD
[ ] ln_get_object_rst_horizon Rise/set over a custom horizon elevation

Orbital Mechanics

Status libnova module Description
[ ] Elliptic motion Position/velocity on an elliptic orbit — Meeus ch. 30
[ ] Parabolic motion Position on a parabolic (cometary) orbit — Meeus ch. 34
[ ] Hyperbolic motion Position on a hyperbolic orbit — Meeus ch. 35

Asteroids & Comets

Status libnova module Description
[ ] Asteroids Heliocentric coords, magnitude, phase, RST for minor planets
[ ] Comets Heliocentric coords, RST, perihelion calculations

Miscellaneous Utilities

Status libnova function Description
[~] ln_get_dec_location Partially covered by HoursMinSec::from_string / DegMinSec::from_string
[~] ln_get_humanr_location Partially covered by Display impls for HoursMinSec / DegMinSec
[ ] ln_interpolate3 3-point interpolation — Meeus ch. 3
[ ] ln_interpolate5 5-point interpolation — Meeus ch. 3

Implementation Notes

  1. Start with foundations — Nutation (delta_psi, delta_eps) is a dependency of apparent sidereal time, aberration, and apparent stellar positions. Implement it first.
  2. Coordinate transforms — hrz_from_equ and equ_from_ecl are broadly needed; implement these before planet modules.
  3. Solar position is required by most planet magnitude/phase calculations.
  4. VSOP87 — Planet heliocentric coordinates require the VSOP87 series. Consider a separate module or feature flag for the large coefficient tables.
  5. Rise/Set/Transit — Generic implementation in src/rise_set.rs can be reused by Sun, Moon, and all planets.
  6. All new functions must cite the relevant Meeus chapter/equation in doc comments and include unit tests with values from Meeus' worked examples.