Sources and editorial approach

Authorship and responsibility

Sky Map 2000 and its documentation are created and maintained by Marcin Szewczyk-Wilgan. Documentation is written alongside the application, so descriptions of controls, cards and calculations track the current build rather than any generic astronomy copy.

Automated tools may assist research or drafting, but the editorial choices, the source selection, the implementation and the responsibility for the published material stay with the author.

How sources are selected

The project favours named, established and openly documented sources that fit the scope of a browser-based sky atlas. The main catalogue and reference sources are named on the relevant pages and inside object cards where it helps.

• Stars and many stellar fields: HYG Database v44.
• Selected Messier and NGC/IC deep-sky objects: OpenNGC.
• Constellation lines, names, boundaries and Milky Way context: d3-celestial.
• Meteor-shower reference radiants and activity information: the IAU Meteor Data Center and International Meteor Organization.
• Constellation abbreviations: the IAU Style Manual; the constellation layer itself is derived from d3-celestial.
• Planetary physical reference values: NASA/JPL Planetary Physical Parameters.

Meteor-shower catalogue

The bundled meteor catalogue (version 2026.1) is a curated list of 15 major annual showers. The IAU Meteor Data Center supplies shower identities, three-letter codes and reference radiants; the International Meteor Organization calendar checks activity periods, annual peak dates and reference ZHR values. It is maintained as an observing reference, not a live activity feed or forecast.

Constellation abbreviations

The constellation button uses the IAU’s standard three-letter abbreviations for all 88 constellations, paired with their full Latin names. Label positions, line and boundary data come from the d3-celestial-derived map layer; the abbreviations themselves follow the IAU standard.

Catalogue facts and local calculations

Catalogue records describe reference information about an object. Values such as altitude, azimuth, horizon status, rise, set, transit, lunar phase and the displayed positions of the Sun, Moon and planets are calculated in the browser for the selected location and time. The app distinguishes those categories so readers can judge what a value actually means.

The planetary calculations are meant for orientation, learning and everyday observing plans. They are not presented as high-precision ephemerides, telescope-control output or navigation data.

How the guides are written

Each guide starts with the user’s task, then covers the relevant control, the expected result and the boundary where only observing can answer. The goal is to help a visitor move from “what does this button do?” to “what can I reasonably observe from this place and time?” without hiding uncertainty.

Where a feature depends on local conditions, the text says so. Cloud, transparency, light pollution, trees, buildings, terrain, equipment and individual eyesight are not inferred from the map and are not treated as if they were known facts.

Updates, corrections and attribution

Source attribution stays with the documentation and the app’s data notes. When an underlying dataset, feature or explanation changes materially, the affected page is reviewed and its modified date is updated. Questions, corrections and feedback are welcome via m4c.pl.