Functions

earth_barycentric_velocity(dt)

Approximate Earth barycentric velocity in km/s (ICRS equatorial frame).

Uses a circular-orbit approximation. Accuracy ~0.5 km/s (~1.7%), sufficient for stellar aberration correction (~20" effect, ~0.3" error).

Parameters:

Name	Type	Description	Default
dt	datetime	Observation time as a datetime.datetime (UTC). The ~69 s offset between UTC and TT is negligible for this approximation.	required

Returns:

Type	Description
list[float]	[vx, vy, vz] in km/s, ICRS equatorial frame. Pass directly to
list[float]	solve_from_centroids(observer_velocity_km_s=...).

Example::

from datetime import datetime
v = tetra3rs.earth_barycentric_velocity(datetime(2025, 7, 10))
result = db.solve_from_centroids(centroids, ..., observer_velocity_km_s=v)

reset_log_cache()

Re-read Python logging levels for tetra3rs log records.

tetra3rs forwards its Rust log records to Python's logging (logger names follow the Rust module path, e.g. tetra3.solver.solve). Each logger's effective level is cached on first use so that disabled messages cost nothing inside the solver; call this after changing a level (e.g. logging.getLogger("tetra3").setLevel(logging.DEBUG)) so the change takes effect.