Sources

Provides J2000 star positions, magnitudes, B−V colour, distance, spectral information, proper motion, HIP and HR/BSC identifiers, Bayer and Flamsteed designations, constellation membership, and its recorded proper/common names. Asterisms keeps pattern-member stars plus the field-star pool at magnitude 6.5 or brighter, not the complete HYG database.

HYG v4.1 is licensed CC BY-SA 4.0↗. Names in its proper field are shown as HYG records them; they are not all asserted to be IAU-approved. No systematic per-star Working Group on Star Names check has been performed.

Provides the chosen stick-figure line convention for the 88 official constellations. Its line sequences reference Bright Star Catalogue (HR) numbers; Asterisms joins those numbers to HYG and turns consecutive stars into line segments. Some figures are intentionally made of separate paths. Source repository↗.

Copyright © 2005–2023 Marc van der Sluys · CC BY 4.0↗. Cite ConstellationLines, v1.3 (2023-12-18), DOI 10.5281/zenodo.10401591↗.

The IAU standardizes the 88 constellation regions, names, and abbreviations. Asterisms carries those identities through the Stellarium Western sky-culture data below; it does not download IAU boundary polygons. The IAU does not define the line figures used in this app.

Reference authority only; not a separate downloaded production catalogue in Asterisms.

Asterisms uses seven fixed HR-to-position/brightness crosswalk records from Hoffleit et al. (1991) where a ConstellationLines star did not join to HYG v4.1. The rest of the line stars use HYG values. This is a specific VizieR-hosted catalogue, not a general VizieR import.

The CDS catalogue record provides the source citation; no separate redistribution licence is recorded for these seven rows. Asterisms preserves the catalogue identity and does not describe all of VizieR as an ingested source.

Version 2.1.19 calculates observer-relative positions for the Sun, Moon, Mercury through Neptune, and Pluto; lunar phase and illumination; local horizon coordinates; rise/set searches; and solar timing used by the nightly sky, guided-find, and Seek views. Asterisms also uses its equatorial-to-horizontal rotation and sidereal-time routines alongside the app's catalogue-star proper-motion transforms. Selected smaller moon orbits use local JPL Horizons vector snapshots.

Astronomy Engine v2.1.19 · MIT License↗. Calculations run locally; no Astronomy Engine ephemeris dataset is bundled.

Asterisms stores Earth-centred ICRF state vectors for 27 selected moons, 12 comets, and 11 asteroids. The sky reads local samples and interpolates position vectors; Horizons is not queried during animation or object selection. Each target carries a validity interval and withheld-sample angular-error report.

Curated target IDs, Horizons solution identifiers, retrieval time, validity, and validation metrics travel with the local snapshot. The API documentation does not state a separate licence for returned ephemerides; Asterisms does not claim one.

Supplies 300 selected NGC/IC and related deep-sky objects, including all 110 Messier designations. Asterisms uses catalogue IDs, cross-identifications, object types, coordinates, constellation labels, magnitudes and angular dimensions/position angles when available. M102 remains a search alias of M101 rather than a second object.

OpenNGC at commit 75ca7ff090e1d0081a5b08be70eb3bc45ccd9e06 · CC BY-SA 4.0↗. The app keeps a curated subset, not the full NGC/IC database.

Contributes 15 selected pulsars and the available positions, proper motions, spin periods, and binary metadata. Records not present in the selected input are not implied by this count.

ATNF asks users to acknowledge the catalogue and cite Manchester et al. (2005), AJ 129, 1993–2006, plus the catalogue URL; see its usage and citation notes↗. Its PSRCAT software is documented as GPL-3.0-or-later; the source does not state a separate licence for extracted catalogue records, so Asterisms does not label the data BSD.

Contributes 10 selected magnetar names, positions, and proper motions where present. The curated candidate/confirmed status is retained rather than silently promoting candidates.

The catalogue says its information may be used in publications and asks users to cite Olausen & Kaspi (2014), ApJS 212, 6, and its URL. No separate data licence is stated in the captured source record.

Supplies identifiers, ICRS positions, object types, measured distance records where available, and redshift values for 102 curated records and the selected OpenNGC deep-sky targets. The generated catalogue currently includes 274 SIMBAD sourced distance measurements and 42 redshift-only records. Each distance retains its unit, quality, method, uncertainty, and reference when SIMBAD provides them. Redshift is handled separately; it is never treated as an ordinary Euclidean distance.

SIMBAD service data are under ODbL 1.0↗ and request the acknowledgement “This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France” plus Wenger et al. (2000), A&AS 143, 9. Asterisms retains source IDs, snapshot dates, measurement methods, and per-record provenance. Where SIMBAD supplies redshift, the app calculates lookback time using the separately cited Planck 2018 cosmology.

The study reports a geometric distance to the Galactic Centre of 8.275 ± 0.009 (stat) ± 0.033 (sys) kpc. Asterisms uses the measured host-system distance for Sagittarius A*, combines the uncertainty in quadrature for its technical record, and labels the displayed value approximate.

Citation: GRAVITY Collaboration (2022), *Astronomy & Astrophysics* 657, L12. The article provides the measurement used for the Sagittarius A* host-system distance.

Supplies 26 curated host-system records. The selected fields include host coordinates, distance and visual magnitude when available, system multiplicity, and confirmed planet names, radii, masses, and orbital periods. The marker and position belong to the host system, not a fabricated planet offset.

The archive requests an acknowledgement and citation to Christiansen et al. (2025); see its acknowledgement guidance↗. The snapshot provenance does not include a distinct dataset licence statement.

The searchable list contains 12 comets and 11 asteroids, including Ceres, Vesta, Apophis, Bennu, and Ryugu. Their local vectors cover a bounded four-year window; selected moons use hourly samples across a 28-day window. Requests outside a target's recorded validity are reported unavailable.

Horizons commands are curated in src/data/dynamic-targets.json. Rebuild and withheld-sample validation use npm run data:dynamic. JPL Small-Body Database (SBDB) is not used for orbit solutions or physical metadata.

Searchable SIMBAD-referenced events include the supernovae of 1006, 1054, 1572, 1604, 1987A, 2011fe, 2014J, and 2023ixf, plus the GW170817/AT 2017gfo counterpart. Each coordinate identifies a remnant, host/event position, or transient counterpart. These are dated annotations, not persistent bright objects.

SIMBAD-derived records use service data under ODbL 1.0↗; the requested acknowledgement and citation are listed here. No historical brightness curves are modeled.

The searchable historical-only records cover ISON's 2013 fragmentation and the Shoemaker–Levy 9 impacts on Jupiter in 1994. The second record marks Jupiter's position at the first impacts, not a surviving comet fragment. Both positions are timestamped JPL Horizons vectors; neither comet is propagated as a current body. See NASA's Shoemaker–Levy 9 event summary↗.

Event lifecycle context is sourced from NASA Science; sky coordinates for each dated marker are separately identified as JPL Horizons positions. No brightness history or live comet trajectory is inferred.

The same-origin route retrieves OMM JSON for the ISS (ZARYA), NORAD 25544. It caches the set for 30 minutes and serves a dated last-known-good snapshot if the upstream request fails. The browser propagates it locally; observer location is never sent to CelesTrak.

Refresh follows the CelesTrak usage policy↗: cache GP data and avoid frequent repeat downloads. Fresh means an epoch up to 12 hours old; aging means 12–48 hours; stale means over 48 hours, when the precise marker is suppressed. The selected date must also be within 48 hours of the epoch.

Parses CelesTrak OMM and propagates the ISS with SGP4. Its returned state is TEME (km and km/s); satellite.js converts the position to Earth-fixed coordinates for local azimuth, altitude, slant range, and Earth-shadow calculations.

Version 7.1.0 · MIT License. The library performs calculations only; it supplies no orbital catalogue.

Asterisms preprocesses GeoNames' cities5000 extract into its own server-side place index. It supplies place names, city-centre WGS84 coordinates, country/administrative region, population ranking, and the source timezone identifier. Normal searches query Asterisms' own index; no third-party geocoder is called.

GeoNames data is CC BY 4.0↗ and requests attribution with a link. The city index was retrieved 26 Sep 2026. A city-centre location is approximate; it is not an exact device location.

Provides Western asterism names/line conventions and constellation identity metadata, along with the HIP anchors used to align the illustrations. Its source description identifies the Western culture's 88 regions as the IAU scheme; asterism figures remain cultural pattern conventions.

Western sky-culture text and data are CC BY-SA↗, per the source description. Asterisms uses a transformed subset of the source metadata; it does not claim the Western tradition is the only valid one.

These are Johan Meuris' original illustrations, not AI-generated images. Asterisms bundles 85 Western constellation figures from the packaged sky-culture source; Puppis, Serpens, and Vela currently have no bundled illustration. The source images remain intact on disk; the renderer removes their black background, applies a monochrome treatment and opacity, and aligns each image to three HIP anchors (with supplied ICRS vectors when an anchor star is absent).

Illustrations are under the Free Art License↗. Keep the artist credit and licence when reusing them. Constellation names and anchor metadata have the separate CC BY-SA terms above.

The underlying poem is public domain. Asterisms transcribes its text from the 1889 Macmillan printing of Demeter and Other Poems; the British Library catalogue records Tennyson’s “Vastness” in 1885.

The historical work’s public-domain status does not imply that a modern transcription, digitized scan, or hosting site shares that status. No blanket licence is asserted for those digital materials.