Data description | Celestial Data

Data formats

Geographic datasets are available as GeoJSON (*.geojson) and GeoPackage (*.gpkg). Minified GeoJSON (*.min.geojson) removes whitespace without simplifying geometries. CSV files contain names and attributes without geometry.

The coordinates use the J2000 celestial reference. Right ascension is converted from hours to degrees (15 degrees per hour), then wrapped into [-180, 180]. Declination supplies the latitude-like angle in [-90, 90]. For example, 6h maps to 90 degrees and 18h maps to -90 degrees.

EPSG:4326 is assigned for compatibility with GIS software. These angles describe celestial directions, not terrestrial WGS84 locations. Earth-based distances, areas and basemaps do not acquire astronomical meaning from this encoding. J2000 identifies the reference epoch. The files contain static positions for that epoch.

Geometries were validated with GEOS 3.9.3. Geometric validity does not establish astronomical accuracy or catalog completeness. Some degenerate source lines were removed during conversion.

Distribution

The website, GitHub and jsDelivr provide alternative URLs for the same files. These URLs follow the main branch. The collection DOI lists the archived releases. https://doi.org/10.5281/zenodo.7561601.

For example, download the minified Milky Way dataset from:

<!-- From GitHub -->
https://raw.githubusercontent.com/dieghernan/celestial_data/main/data/mw.min.geojson

<!-- From the Website -->
https://dieghernan.github.io/celestial_data/data/mw.min.geojson

<!-- From jsDelivr -->
https://cdn.jsdelivr.net/gh/dieghernan/celestial_data@main/data/mw.min.geojson

Downloads

Browse the download catalog for all datasets, file sizes and links to individual dataset pages.

Description

Asterisms

asterisms.<data format> (MULTILINESTRING) with 65 features and the following attributes:

id: Name without spaces
n: Proper name
es: Proper name in Spanish
p: Display priority (1–6), approximately related to brightness. A value of 6 denotes a guide line
loc_lon, loc_lat: Label position in the same angular encoding as the geometry

Constellations

constellations.<data format> (POINT) with 89 objects. Additionally a constellations.csv file with the attributes (no geometry) is also provided. The points are label positions, not constellation regions. The 89 records include separate entries for Serpens Caput and Serpens Cauda:

id: 3-letter designator
name: Full IAU name
desig: 3-letter designator again
gen: Genitive form used for naming stars
rank: 1-3 for differential name display by size/brightness
en: English name. Other fields provide names in additional languages
display_ra, display_dec, display_scale: View center and scale for displaying a single constellation. These are display parameters

Traditional Chinese constellations

constellations.cn.<data format> (POINT) with 312 objects. Additionally a constellations.cn.csv file with the attributes (no geometry) is also provided:

id: Numerical identifier
name: Chinese name
en: English translation
pinyin: Pinyin transcription
desig: Chinese name repeated for compatibility
rank: Display priority. The value is currently 1 in this dataset
display_ra, display_dec, display_scale: View center and scale for displaying a single constellation. These are display parameters

Constellation boundaries

constellations.borders.<data format> (MULTILINESTRING) with 257 objects.

ids: String with format “3-letter designator A, 3-letter designator B” identifying the constellations surrounding the border.

constellations.bounds.<data format> (MULTIPOLYGON) with 89 objects. See Constellation lines for field descriptions.

Traditional Chinese constellations

constellations.borders.cn.<data format> (LINESTRING) with 84 objects.

ids: Border identifier

constellations.bounds.cn.<data format> (POLYGON) with 28 objects. See Constellation lines for field descriptions.

Constellation lines

constellations.lines.<data format> (MULTILINESTRING) with 89 objects.

id: 3-letter designator
rank: 1-3 for differential name display by size/brightness
name: Full IAU name

Traditional Chinese constellations

constellations.lines.cn.<data format> (MULTILINESTRING) with 255 features.

Some records were removed from the original dataset because their line geometry contained only one position. A GeoJSON LineString requires at least two positions. A MultiLineString contains arrays of such lines.

id: Numerical identifier
rank: Display priority. The value is currently 1 in this dataset
name: Chinese name
en: English translation

DSOs

Deep-sky objects (DSOs) include galaxies, nebulae and star clusters.

DSO names

dsonames.csv with 724 rows:

id: Short designator
name: Proper name. Other fields provide translations

Traditional Chinese DSO names

dsonames.cn.csv with 6 rows:

id: Deep-sky catalog designation, such as NGC 224
name: Chinese name
desig: Catalog designation
en: English translation
pinyin: Pinyin transcription

DSOs

Several files:

dsos.6.<data format>, dsos.14.<data format>, dsos.20.<data format>: the number indicates the nominal limiting magnitude.
dsos.bright.<data format>: hand selected DSOs.
lg.<data format>: Local group.
messier.<data format> Messier objects.

These catalogs contain POINT geometries. Attributes vary between catalogs; for example, Messier includes alt and cl but does not include bv or morph. Unknown magnitudes (999) must be excluded from numeric magnitude filters and brightness calculations.

Common attributes include:

id: Short designator
desig: Designator
type: Object type: gg (galaxy cluster), g: (galaxy), s: (spiral galaxy), s0: (lenticular gal.), sd: (dwarf spheroidal gal.), i: (irregular gal.), e: (elliptical gal.), oc: (open cluster), gc: (globular cluster), dn: (dark nebula), bn: (bright nebula), sfr: (star forming region), rn: (reflection nebula), en: (emission nebula), pn: (planetary nebula), snr: (supernova remnant).
morph: Morphology classification depending on type
mag: Apparent magnitude. The value 999 indicates an unavailable value
dim: Angular dimensions in arcminutes
bv: Blue-minus-visual color index (B−V)
br: Relative brightness compared with magnitude 0, computed as \(100^{-1 * mag / 5}\)
name: Proper name

Additional fields on lg.<data format>:

sub: Sub group membership: MW|M31|N3109|LG (Milky Way, Andromeda, NGC 3109, gen. LG)
pop: MW populations OH|YH|BD (Old halo, young halo, bulge & disk), M31 populations M31|GP (gen. M31, great plane)
str: Tidal streams Mag|Sgr|CMa|FLS (Magellanic Stream, Sagittarius Stream, Canis Major/Monoceros Stream, Fornax-Leo-Sculptor Great Circle)

Stars

Star names

starnames.csv has 4869 rows of names and designations, independent of the star catalog magnitude subsets. Some name fields are empty or unavailable.

id: Hipparcos number
name: Proper name. Other fields provide translations
desig: Preferred display designation from the available catalog names
bayer: Bayer designation
flam: Flamsteed designation
var: Variable star designation
gl, gliese: Gliese designation fields
hd: Henry Draper catalog designation
hip: Hipparcos number again

Traditional Chinese star names

starnames.cn.csv with 3056 rows:

id: Hipparcos number
name: Chinese name
desig: Catalog designation
en: English translation
pinyin: Pinyin transcription

Stars

stars.6.<data format>, stars.8.<data format>, stars.14.<data format>: the number indicates the nominal limiting magnitude. Smaller magnitudes indicate brighter objects. The local stars.8 file reaches magnitude 8.0, although the upstream project describes its current counterpart as reaching 8.5. These subsets do not guarantee a complete survey of all objects to that magnitude:

id: Star identifier (Hipparcos number)
mag: Apparent magnitude. The value 999 indicates an unavailable value
bv: Blue-minus-visual color index (B−V)
br: Relative brightness compared with magnitude 0, computed as \(100^{-1 * mag / 5}\)
name: Proper name

Milky Way

mw.<data format> with 5 rows:

id: Milky Way outlines in 5 brightness steps (ol1-ol5).