skyfield-data
Data package for Skyfield
Decision gist · record as of 2026-08-14
Yes, if you need offline astronomical data files. Install alongside dependent libraries and point loaders to its data path. Be aware that data files expire (de421.bsp in 2053, finals2000A.all in 2026); you must upgrade the package before expiration to maintain accuracy. The 353-day gap since the last release suggests maintenance is not rapid, so monitor expiration dates and plan upgrades accordingly.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Data files have expiration dates (de421.bsp expires 2053-10-08, finals2000A.all expires 2026-10-18); package must be upgraded before expiration to avoid stale data.
- Low friction installation as a pure data wheel with no runtime dependencies.
- Last release was 353 days ago; the package is in aging maintenance status.
License · maintenance · safety
MIT (permissive) — MIT license permits unrestricted use, modification, and distribution. Data files themselves (de421.bsp from JPL, finals2000A.all from IERS) are provided under their respective institutional terms; the Python package code is MIT-licensed.
last release 2025-08-26 (353 days) · last repo commit 2025-08-26 · 14 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 98,916 downloads/mo, #13,050 on PyPI
Alternatives
Verify before relying
pip install skyfield-data
from skyfield_data import get_skyfield_data_path
from skyfield.api import Loader
load = Loader(get_skyfield_data_path())
planets = load('de421.bsp')- Whether all data files in version 7.0.0 remain within their expiration windows as of August 2026.
- Current compatibility status with Python 2.6 given the noted defunct CI for that version.
- Whether the package is actively maintained or in maintenance-only mode given the 353-day release gap.
- How frequently this package is updated relative to data file expiration schedules.
What it is and what it does
skyfield-data is a data distribution package that bundles the ephemeris and Earth rotation files required for astronomical calculations. Instead of having dependent libraries download these large files at runtime (which can cause delays, timeouts, or network failures), this package installs them locally via pip, allowing offline computation and eliminating dependency on NASA JPL or IERS availability.
The package includes de421.bsp (planetary ephemeris) and finals2000A.all (Earth orientation data), with built-in expiration tracking. When you instantiate a Loader pointing to the data path provided by this package, computations use the local files without triggering downloads. The package emits warnings when files approach or pass their expiration dates, signaling when an upgrade is needed to maintain accuracy.
Use it for
- Offline astronomical computation in environments without reliable internet access or behind restrictive network proxies.
- Web applications requiring predictable startup time and avoiding runtime downloads that could timeout client requests.
- Containerized deployments where reproducible, pre-cached data files reduce image size and startup latency.
- Long-running services that need to compute moon phases, planet positions, or timescale data without external dependencies.
- Development and testing workflows where consistent, versioned data ensures reproducible astronomical calculations.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you need offline astronomical data files.
Install alongside dependent libraries and point loaders to its data path. Be aware that data files expire (de421.bsp in 2053, finals2000A.all in 2026); you must upgrade the package before expiration to maintain accuracy. The 353-day gap since the last release suggests maintenance is not rapid, so monitor expiration dates and plan upgrades accordingly.
Install
skyfield-data on PyPI
Before you install
Low friction installation as a pure data wheel with no runtime dependencies. Last release was 353 days ago; the package is in aging maintenance status. Repository is not archived and receives commits.
Data files have expiration dates (de421.bsp expires 2053-10-08, finals2000A.all expires 2026-10-18); package must be upgraded before expiration to avoid stale data.
License in practice
MIT license permits unrestricted use, modification, and distribution. Data files themselves (de421.bsp from JPL, finals2000A.all from IERS) are provided under their respective institutional terms; the Python package code is MIT-licensed.
Quickstart
pip install skyfield-data
from skyfield_data import get_skyfield_data_path
from skyfield.api import Loader
load = Loader(get_skyfield_data_path())
planets = load('de421.bsp')Verify before relying
- Whether all data files in version 7.0.0 remain within their expiration windows as of August 2026.
- Current compatibility status with Python 2.6 given the noted defunct CI for that version.
- Whether the package is actively maintained or in maintenance-only mode given the 353-day release gap.
- How frequently this package is updated relative to data file expiration schedules.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release !=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,!=3.5.*,!=3.6.*,!=3.7,<4,>=2.6 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | None |
| Maintenance | Aging 353 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 98,916 / month, #13,050 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: PythonProgramming Language :: Python :: 2.6Programming Language :: Python :: 2.7Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9 |
Evidence: skyfield_data-7.0.0-py2.py3-none-any.whl
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