COMPATIBILITY_NOTES_5.2.2

Compatibility Notes - Moira 5.2.2

Date: 2026-07-25

Moira 5.2.2 preserves the public result vessels and existing positional call forms, but it intentionally changes several lunar-point longitudes and asteroid-family memberships to repair hidden frame and catalog semantics. Consumers that freeze exact node values or assume one exclusive asteroid family should review the changes below.

True-node longitude correction

true_node(jd_ut, reader=None) retains its signature and NodeData result. Its longitude now comes from a common-frame osculating-plane/ecliptic-plane intersection.

The numerical correction depends on epoch and grows away from J2000 in the previous implementation. Representative defects repaired by this release include approximately +39.3 arcseconds in 1967, -29.2 arcseconds in 2026, and +139 arcseconds in the shipped 1625 comparison case.

Applications with saved true-node charts, exact aspect boundaries, transit times, or draconic charts should regenerate affected results.

Mean-node and Mean-Lilith default frame

The signatures are now:

mean_node(jd_ut, *, nutation=True)
mean_lilith(jd_ut, *, nutation=True)

The default True value expresses the analytical mean orbital point in the true ecliptic and equinox of date, matching the rest of a default Moira chart. This shifts prior default longitudes by nutation in longitude, generally by a few arcseconds and up to roughly 19 arcseconds over the tested historical and modern interval.

Use nutation=False when a raw mean-equinox-of-date analytical longitude is required. The mean-node polynomial itself is now the IERS 2003 expression, so nutation=False is the correct frame-compatible replacement but is not a promise of bit-for-bit reproduction of the older duplicated coefficients.

NodeData.speed for the mean node is the derivative of the governing IERS mean argument. It deliberately excludes the short-period derivative of nutation even when the longitude is returned in the true frame.

Chart reduction response

Each entry in reduction.node_reductions now includes:

• nutation: true
• frame: "true_ecliptic_and_equinox_of_date"

Mean-node and mean-Lilith stage sequences also include the IAU 2000A nutation conversion. Strict response consumers must admit these two additive fields.

Asteroid-family catalog behavior

The family catalog is now a many-to-many Proper25/PDS product. Consumers must not interpret family as exclusive physical membership.

• Use the complete families collection when grouping or constructing resonance networks.
• Treat the display-primary family value as a deterministic compatibility selection only.
• Expect memberships, family sizes, and aliases to differ from the earlier legacy catalog.
• A null or absent family remains meaningful: it means the numbered asteroid is absent from the admitted Proper25/PDS catalogs, not that the asteroid has been proven to have no family.

The aliases Koronis(2), RJ, and UV209 resolve to the normalized family identifiers without duplicating membership rows.

Upgrade action

Pin and install:

moira-astro==5.2.2

Restart every process that imports Moira, regenerate cached charts containing lunar nodes or Mean Lilith, and refresh any derived asteroid-family grouping or resonance artifacts.