V1, V2 and V3 are product phases. Releases use Semantic Versioning independently of those labels.
64-bit Microsoft 365 Excel on Windows; downloadable XLSM package; full native Swiss Ephemeris coverage, Swiss-style worksheet interfaces and friendly helpers; guided reference sheets. Exactly three binary data files plus sefstars.txt, seasnam.txt and seorbel.txt.
Version 0.1.0-dev.4 implements and exercises all 106 interfaces, fractional-offset UTC/UT1/TT conversion, houses, date-series helpers and worked examples. Downloaded-package onboarding and desktop checks passed on the existing Windows profile on 2026-10-07. Publish the tested development preview with this limitation; clean-profile acceptance remains required before stable 1.0. PLAN.md records the complete specification.
Verify and document Excel 2024 compatibility. Investigate IANA named time zones, historical DST, database provenance and updates. Decide whether named-zone support belongs in V2 or V3 after the investigation.
Name the exact supported editions/builds. Design compatible array entry and output behavior for editions without modern spilling arrays; verify each supported version.
Investigate a hosted Office add-in: Excel loads a web-hosted extension that adds formulas and reference UI. Explore a WebAssembly Swiss Ephemeris engine for Mac and browser Excel, deployment and updates, licensing/source delivery, data downloads and offline behavior. A downloadable VBA workbook and a hosted add-in have different build and distribution requirements.
Create a separate feature and implementation plan for chart wheels, saved profiles, aspects, comparisons, transit workflows and Cosmodynes. Use the legacy workbook as behavioral evidence; do not silently transfer its mutable-global state, indexing quirks or calculation bugs into the toolkit.
Broader date ranges, Eros and other numbered asteroids/centaurs, planetary moons and raw JPL files. Document per-file/body coverage, size, naming and directories. Eros is not bundled in V1. Numbered asteroid files use astN/ where N is the MPC number divided by 1000 with the remainder discarded; body ID is 10000 plus MPC number. These packs require their own manifest and verification.