Status: verified draft, first audit pass; Phase 1–4 row corrections applied 2026-04-04.

This document is a corrected first pass over an AI-generated Swiss Ephemeris translation draft. It is intentionally narrower than the original text. Only mappings verified against the current repository surface are stated as facts here.

Use this as:

• a migration guide for the audited subset
• a correction log for the original draft
• a checklist for the remaining unaudited pyswisseph surface

Do not treat this file as a complete 420-symbol authoritative map yet.

For inventory purposes, each Swiss symbol should eventually land in one of these buckets:

• mapped — a clear Moira equivalent exists now
• partial — the intent exists, but the shape is split or not strictly 1:1
• stdlib — use Python or another non-Moira standard tool instead
• missing — no current Moira equivalent
• unsupported — intentionally outside Moira's design scope

For the 104 symbol rows currently inventoried from the generated draft:

• mapped: 61
• partial: 35
• stdlib: 5
• missing: 3
• unsupported: 4

These totals are for the audited rows in this document, not yet for the full published pyswisseph symbol surface.

The original draft had several structural errors:

• The real constructor is Moira(kernel_path=...), not Moira(ephe_path=...).
• There is no Moira.planet(...) facade method in the current repo.
• There is no public moira.models.Observer layer in the current repo.
• Rise/set lives in moira.rise_set, not moira.riseset.
• Ayanamsa constants live in moira.sidereal.Ayanamsa, not moira.constants.
• Planet result vessels do not expose Swiss-shaped fields like speed_longitude; PlanetData uses speed.
• PlanetData.distance and SkyPosition.distance are stored in kilometers, not AU.

Swiss Ephemeris is a flag-driven C API with global mutable state. Moira is a typed Python engine with:

• explicit arguments instead of global setters
• typed result vessels instead of tuples
• facade methods for common workflows
• lower-level engine functions for specialist access

Some migrations are therefore semantic rather than signature-identical.

Swiss global ephemeris path:

import swisseph as swe
swe.set_ephe_path("/path/to/ephe")
swe.set_jpl_file("de441.eph")

Moira constructor or reader setup:

from moira import Moira

m = Moira(kernel_path="/path/to/de441.bsp")

There is also a lower-level kernel path hook:

from moira.spk_reader import set_kernel_path

set_kernel_path("/path/to/de441.bsp")

Swiss global topo observer:

swe.set_topo(lon, lat, alt)

Moira does not keep global observer state. Pass observer coordinates per call:

from moira.planets import sky_position_at

sky = sky_position_at(
    "Moon",
    jd_ut,
    observer_lat=lat,
    observer_lon=lon,
    observer_elev_m=alt,
)

There is no swe.close() equivalent.

Verified equivalents in moira.julian:

Important difference:

• delta_t() currently takes a decimal year, not a JD.
• The original draft's utc_to_jd() and jd_to_utc() names do not match the current public surface I have verified in moira.julian.

The audited low-level engine entry points are in moira.planets:

from moira.planets import planet_at, sky_position_at, all_planets_at

Low-level geocentric ecliptic position:

pos = planet_at("Sun", jd_ut)
pos.longitude
pos.latitude
pos.distance   # kilometers
pos.speed      # degrees/day

Topocentric sky position:

sky = sky_position_at(
    "Moon",
    jd_ut,
    observer_lat=lat,
    observer_lon=lon,
    observer_elev_m=alt,
)
sky.right_ascension
sky.declination
sky.azimuth
sky.altitude
sky.distance   # kilometers

Facade-level whole-chart workflow:

from moira import Moira

m = Moira(kernel_path="/path/to/de441.bsp")
chart = m.chart(dt, observer_lat=lat, observer_lon=lon, observer_elev_m=alt)
sun = chart.planets["Sun"]

Important corrections to the original draft:

• There is no audited m.planet(...) facade method.
• The nearest stable facade equivalent is usually m.chart(...) or m.sky_position(...).
• The low-level equivalent for Swiss calc_ut() is planet_at(...).

Facade:

from moira import Moira
from moira.constants import HouseSystem

m = Moira()
houses = m.houses(dt, latitude=lat, longitude=lon, system=HouseSystem.PLACIDUS)

Low-level:

from moira.houses import calculate_houses

houses = calculate_houses(jd_ut, lat, lon, HouseSystem.PLACIDUS)

Verified current fact:

• calculate_houses(...) exists.
• The original draft's houses_from_armc and body_house_position claims are not yet audited in this pass and are intentionally omitted here.

Verified surface is in moira.sidereal:

from moira.sidereal import Ayanamsa, ayanamsa

offset = ayanamsa(jd_ut, Ayanamsa.LAHIRI)

Important correction:

• Ayanamsa does not live in moira.constants.
• The original draft's ayanamsa_value(...) name does not match the current audited function; the verified function is ayanamsa(...).

Low-level audited surface:

from moira.fixed_stars import fixed_star_at, list_stars, find_stars, star_magnitude

spica = fixed_star_at("Spica", jd_tt)
mag = star_magnitude("Spica")

Facade:

from moira import Moira

m = Moira()
spica = m.fixed_star("Spica", dt)

Important correction:

• The fixed-star low-level function expects jd_tt, not jd_ut.
• The facade accepts a datetime and handles conversion.

The current eclipse engine is class-based, not a flat top-level function set.

Verified surface:

from moira.eclipse import EclipseCalculator

calc = EclipseCalculator()
solar = calc.next_solar_eclipse(jd_start)
lunar = calc.next_lunar_eclipse(jd_start)

Facade-level single-moment eclipse evaluation also exists:

from moira import Moira

m = Moira()
data = m.eclipse(dt)

Important correction:

• The original draft's top-level imports like from moira.eclipse import next_solar_eclipse are not verified as current public functions in this repo.
• The audited current shape is EclipseCalculator.next_solar_eclipse(...) and EclipseCalculator.next_lunar_eclipse(...).

Verified surface is in moira.rise_set:

from moira.rise_set import find_phenomena, get_transit, twilight_times

events = find_phenomena("Sun", jd_start, lat, lon)
upper = get_transit("Sun", jd_start, lat, lon, upper=True)
lower = get_transit("Sun", jd_start, lat, lon, upper=False)
twilight = twilight_times(jd_day, lat, lon)

Important correction:

• The module is rise_set, not riseset.
• The current API is event-dictionary based, not next_rise(...) / next_set(...) wrappers.

Verified facade:

from moira import Moira

m = Moira()
nodes = m.planetary_nodes(dt)

Verified low-level:

from moira.planetary_nodes import all_planetary_nodes

nodes = all_planetary_nodes(jd_ut)

The original draft's exact lunar_nodes(...) / next_moon_node_crossing(...) mapping is not yet audited here.

Verified facade:

from moira import Moira

m = Moira()
events = m.phenomena("Venus", jd_start, jd_end)
phases = m.moon_phases(jd_start, jd_end)

Verified low-level:

from moira.phenomena import moon_phases_in_range

phases = moon_phases_in_range(jd_start, jd_end)

Important correction:

• The original draft's planetary_phenomena(...) function name is not yet audited as a current public function in this repo.

The following original-draft areas still need explicit symbol-by-symbol review before they can be treated as authoritative:

• exact Swiss flag-to-keyword mapping table
• body constant mapping table
• house-system code mapping table
• coordinate transform helper mapping
• heliacal mapping
• occultation mapping
• gauquelin mapping details
• asteroid and arbitrary-body migration examples
• "not yet implemented" completeness table

This is not yet the full 420-symbol matrix, but it is now explicit about what is already covered versus what still needs inclusion.

These are the items from the generated draft that still look genuinely absent or not yet verified as present in the current repo.

• set_lapse_rate
• lat_to_lmt
• lmt_to_lat
• get_current_file_data
• get_library_path
• get_tid_acc
• set_tid_acc

• full Swiss flag table (FLG_*)
• full body constant table against current Moira naming
• full ayanamsa constant table against moira.sidereal.Ayanamsa
• exact house-system byte-code mapping table
• exact coordinate-transform helper parity
• exact planetary-phenomena parity with Swiss pheno_ut

• lunar occultations
• star occultation support
• Uranian bodies
• asteroid kernel introspection
• station and retrograde search
• returns and syzygy helpers

Based on this pass alone, the honest "needs inclusion" list is much smaller than the generated draft implied.

High confidence missing utility surface:

• explicit tidal-acceleration override getters/setters if Swiss parity matters
• Swiss-style local-mean-time helper utilities if you want migration parity
• any file-introspection helpers analogous to Swiss library/file-path queries

Everything else above should be treated as "needs exact mapping work" before it is treated as missing.

This section is the more literal inventory pass: one row per Swiss symbol named in the generated draft, with the best current status from this audit.

If Swiss parity is the goal, these are the clearest items still needing real Moira surface rather than just mapping work:

Implemented (Phase 1–4):

• DeltaTPolicy closes set_delta_t_userdef (Phase 1)
• horizontal_to_equatorial closes azalt_rev (Phase 1)
• atmospheric_refraction / atmospheric_refraction_extended close refrac / refrac_extended (Phase 1)
• equation_of_time closes time_equ (Phase 1)
• houses_from_armc / body_house_position close houses_armc / house_pos (Phase 2)
• planet_relative_to closes calc_pctr (Phase 2)
• next_moon_node_crossing closes mooncross_node_ut (Phase 2)
• next_heliocentric_transit closes helio_cross_ut (Phase 2)
• orbital_elements_at / distance_extremes_at close get_orbital_elements / orbit_max_min_true_distance (Phase 4)
• visual_limiting_magnitude closes vis_limit_mag (Phase 5 / V6)
• ayanamsa_offset kwarg on calculate_houses and houses_from_armc closes houses_ex / houses_armc_ex2 sidereal parity
• VisibilityAssessment.solar_elongation_deg closes heliacal_pheno_ut (Phase 5 / V6)

Still missing:

• local-mean-time utility helpers (lat_to_lmt, lmt_to_lat)
• tidal-acceleration override helpers (get_tid_acc, set_tid_acc)
• library/file introspection helpers (get_library_path, get_current_file_data)

If you are migrating off pyswisseph today, prefer this Moira shape:

from moira import Moira
from moira.constants import HouseSystem
from moira.planets import planet_at, sky_position_at
from moira.rise_set import find_phenomena, get_transit
from moira.sidereal import Ayanamsa, ayanamsa

m = Moira(kernel_path="/path/to/de441.bsp")
chart = m.chart(dt, observer_lat=lat, observer_lon=lon)
houses = m.houses(dt, lat, lon, HouseSystem.PLACIDUS)
sun = chart.planets["Sun"]
moon_sky = m.sky_position(dt, "Moon", lat, lon)
events = find_phenomena("Sun", jd_start, lat, lon)
lahiri = ayanamsa(jd_ut, Ayanamsa.LAHIRI)

This draft should be extended only by checking each claimed mapping against the live repo surface first.