SIMBAD Astronomical Database (CDS Strasbourg)

Base URLs

TAP endpoint (recommended):

https://simbad.cds.unistra.fr/simbad/sim-tap/sync

Legacy script interface:

https://simbad.cds.unistra.fr/simbad/sim-script

Simple query endpoints:

https://simbad.cds.unistra.fr/simbad/sim-id
https://simbad.cds.unistra.fr/simbad/sim-coo

Authentication

No API key required. All endpoints are public.

Key Endpoints

1. TAP Queries (ADQL — recommended for programmatic use)

GET /simbad/sim-tap/sync?request=doQuery&lang=adql&format={format}&query={ADQL}

Parameter	Type	Description
`request`	string	`doQuery`
`lang`	string	`adql`
`format`	string	`json`, `votable`, `csv`, `tsv`.
`query`	string	Required. ADQL query.

Example — look up object by name:

https://simbad.cds.unistra.fr/simbad/sim-tap/sync?request=doQuery&lang=adql&format=json&query=SELECT basic.OID, ra, dec, main_id, otype FROM basic JOIN ident ON oid = ident.oidref WHERE id = 'M31'

Example — cone search (objects within 5 arcmin of coordinates):

https://simbad.cds.unistra.fr/simbad/sim-tap/sync?request=doQuery&lang=adql&format=json&query=SELECT TOP 50 main_id, ra, dec, otype FROM basic WHERE CONTAINS(POINT('ICRS', ra, dec), CIRCLE('ICRS', 10.684, 41.269, 0.083)) = 1

Note: radius in CIRCLE is in degrees (5 arcmin = 0.083 deg).

Example — objects by type (e.g., all pulsars):

https://simbad.cds.unistra.fr/simbad/sim-tap/sync?request=doQuery&lang=adql&format=json&query=SELECT TOP 100 main_id, ra, dec, otype FROM basic WHERE otype = 'Pulsar'

2. Identifier Query (simple lookup)

GET /simbad/sim-id?Ident={name}&output.format=votable

Parameter	Type	Description
`Ident`	string	Required. Object name (e.g., `M31`, `Sirius`, `NGC 1275`).
`output.format`	string	`votable`, `html`.

Example:

https://simbad.cds.unistra.fr/simbad/sim-id?Ident=M31&output.format=votable

3. Coordinate Query

GET /simbad/sim-coo?Coord={coords}&Radius={radius}&Radius.unit={unit}&output.format=votable

Parameter	Type	Description
`Coord`	string	Required. Coordinates, e.g., `10.684 +41.269` or `00 42 44 +41 16 09`.
`Radius`	float	Search radius. Default: 2.
`Radius.unit`	string	`arcmin`, `arcsec`, `deg`. Default: `arcmin`.
`output.format`	string	`votable`, `html`.

Example:

https://simbad.cds.unistra.fr/simbad/sim-coo?Coord=10.684+%2B41.269&Radius=5&Radius.unit=arcmin&output.format=votable

4. Script Interface (for multi-command queries)

POST /simbad/sim-script
Content-Type: application/x-www-form-urlencoded
script=format+object+"%MAIN_ID+|+%RA+|+%DEC+|+%OTYPE"\nquery+id+M31

Key TAP Tables

Table	Description
`basic`	Core data: coordinates, main_id, object type.
`ident`	All known identifiers for objects.
`flux`	Flux/magnitude measurements.
`mesVelocities`	Radial velocity measurements.
`mesDistance`	Distance measurements.
`otypedef`	Object type definitions/labels.
`allfluxes`	All flux data joined.

Common Object Types (otype)

Star, Galaxy, Pulsar, QSO, Nebula, GlobCluster, RadioSource, X-raySource, SNRemnant

Response Format (TAP JSON)

json

{
  "metadata": [
    {"name": "main_id", "datatype": "char"},
    {"name": "ra", "datatype": "double"},
    {"name": "dec", "datatype": "double"}
  ],
  "data": [
    ["M 31", 10.6847, 41.2687]
  ]
}

Rate Limits

No formal rate limits documented. SIMBAD requests that automated scripts include reasonable delays between queries. Very large TAP queries may time out; use TOP N to limit results or switch to async TAP at /simbad/sim-tap/async.