EphCore.Stars.Position (eph_core v0.1.0)

Fixed-star position computation from Hipparcos catalog records.

Applies proper motion, converts to ecliptic and equatorial-of-date coordinates, and optionally projects to local altitude/azimuth.

For large N, prefer compute_many/3 — it builds the per-epoch precession/ nutation matrix (and observer local basis) once and reuses them across stars.

Summary

Functions

compute(star, jd_tt, opts \\ [])

Computes the full sky position of a catalog star at the given Julian Date (TT).

compute_many(stars, jd_tt, opts \\ [])

Computes positions for many catalog stars at one epoch.

Types

observer()

@type observer() :: %{lat_deg: float(), lon_deg: float(), height_m: float()}

result()

@type result() :: %{
  ecliptic_lon_deg: float(),
  ecliptic_lat_deg: float(),
  ra_deg: float(),
  dec_deg: float(),
  altitude_deg: float() | nil,
  azimuth_deg: float() | nil,
  magnitude: float(),
  name: String.t() | nil,
  hip: integer()
}

star_record()

@type star_record() :: EphCore.Stars.Catalog.star_record()