VO Simple Cone Search (astroquery.vo_conesearch)

Warning

As of version 0.4.12, this module has been deprecated. Client-side queries can be made using PyVO Simple Cone Search (SCS) interface instead. However, there is no direct replacement for server validation functionality. If you need help transitioning away from the deprecated functionality here, please reach out to Astroquery or PyVO communities.

Astroquery offers Simple Cone Search Version 1.03 as defined in IVOA Recommendation (February 22, 2008). Cone Search queries an area encompassed by a given radius centered on a given RA and Dec and returns all the objects found within the area in the given catalog.

This was ported from astropy.vo:

• astropy.vo.client.conesearch is now astroquery.vo_conesearch.conesearch

• astropy.vo.validator is now astroquery.vo_conesearch.validator

astroquery.vo_conesearch.ConeSearch is a Cone Search API that adheres to Astroquery standards but unlike Astropy’s version, it only queries one given service URL, which defaults to HST Guide Star Catalog. This default is controlled by astroquery.vo_conesearch.conf.fallback_url.

Default Cone Search Services

For the “classic” API ported from Astropy, the default Cone Search services used are a subset of those found in the STScI VAO Registry. They were hand-picked to represent commonly used catalogs below:

• 2MASS All-Sky

• HST Guide Star Catalog (also default for “new” Astroquery-style API)

• SDSS Data Release 7

• SDSS-III Data Release 8

• USNO A1

• USNO A2

• USNO B1

This subset undergoes daily validations hosted by STScI using Validation for Simple Cone Search. Those that pass without critical warnings or exceptions are used by Simple Cone Search by default. They are controlled by astroquery.vo_conesearch.conf.conesearch_dbname:

1. 'conesearch_good' Default. Passed validation without critical warnings and exceptions.

2. 'conesearch_warn' Has critical warnings but no exceptions. Use at your own risk.

3. 'conesearch_exception' Has some exceptions. Never use this.

4. 'conesearch_error' Has network connection error. Never use this.

If you are a Cone Search service provider and would like to include your service in the list above, please open a GitHub issue on Astroquery.

Caching

Caching of downloaded contents is controlled by astropy.utils.data. To use cached data, some functions in this package have a cache keyword that can be set to True.

Getting Started

This section only contains minimal examples showing how to perform basic Cone Search.

Query STScI Guide Star Catalog using “new” Astroquery-style API around M31 with a 0.1-degree search radius:

>>> from astropy.coordinates import SkyCoord
>>> from astroquery.vo_conesearch import ConeSearch
>>> c = SkyCoord.from_name('M31')
>>> c
<SkyCoord (ICRS): (ra, dec) in deg
    (10.6847083, 41.26875)>
>>> result = ConeSearch.query_region(c, '0.1 deg')
>>> result
<Table length=4028>
    objID           gsc2ID      gsc1ID ... multipleFlag compassGSC2id   Mag
                                       ...                              mag
    int64           object      object ...    int32         int64     float32
-------------- ---------------- ------ ... ------------ ------------- -------
23323175812944 00424433+4116085        ...            0 6453800072293   9.453
23323175812948 00424403+4116069        ...            0 6453800072297   9.321
23323175812933 00424455+4116103        ...            0 6453800072282  10.773
23323175812939 00424464+4116092        ...            0 6453800072288   9.299
23323175812930 00424403+4116108        ...            0 6453800072279  11.507
23323175812931 00424464+4116106        ...            0 6453800072280   9.399
           ...              ...    ... ...          ...           ...     ...
  133001227000     N33001227000        ...            0 6453800007000 20.1382
 1330012244001    N330012244001        ...            0 6453800044001 21.8968
 1330012228861    N330012228861        ...            0 6453800028861 20.3572
 1330012212014    N330012212014        ...            0 6453800012014 16.5079
 1330012231849    N330012231849        ...            0 6453800031849 20.2869
 1330012210212    N330012210212        ...            0 6453800010212 20.2767
>>> result.url
'http://gsss.stsci.edu/webservices/vo/ConeSearch.aspx?CAT=GSC23'

List the available Cone Search catalogs that passed daily validation:

>>> from astroquery.vo_conesearch import conesearch
>>> conesearch.list_catalogs()
Downloading https://astroconda.org/aux/vo_databases/conesearch_good.json
|==========================================|  59k/ 59k (100.00%)         0s
['Guide Star Catalog 2.3 Cone Search 1',
 'SDSS DR7 - Sloan Digital Sky Survey Data Release 7 1',
 'SDSS DR7 - Sloan Digital Sky Survey Data Release 7 2', ...,
 'Two Micron All Sky Survey (2MASS) 2']

Query the HST Guide Star Catalog around M31 with a 0.1-degree search radius. This is the same query as above but using “classic” Astropy-style API:

>>> from astropy import units as u
>>> my_catname = 'Guide Star Catalog 2.3 Cone Search 1'
>>> result = conesearch.conesearch(c, 0.1 * u.degree, catalog_db=my_catname)
Trying http://gsss.stsci.edu/webservices/vo/ConeSearch.aspx?CAT=GSC23&
WARNING: W50: ...: Invalid unit string 'pixel' [...]
>>> result
<Table length=4028>
    objID           gsc2ID      gsc1ID ... multipleFlag compassGSC2id   Mag
                                       ...                              mag
    int64           object      object ...    int32         int64     float32
-------------- ---------------- ------ ... ------------ ------------- -------
23323175812944 00424433+4116085        ...            0 6453800072293   9.453
23323175812948 00424403+4116069        ...            0 6453800072297   9.321
23323175812933 00424455+4116103        ...            0 6453800072282  10.773
23323175812939 00424464+4116092        ...            0 6453800072288   9.299
23323175812930 00424403+4116108        ...            0 6453800072279  11.507
23323175812931 00424464+4116106        ...            0 6453800072280   9.399
           ...              ...    ... ...          ...           ...     ...
  133001227000     N33001227000        ...            0 6453800007000 20.1382
 1330012244001    N330012244001        ...            0 6453800044001 21.8968
 1330012228861    N330012228861        ...            0 6453800028861 20.3572
 1330012212014    N330012212014        ...            0 6453800012014 16.5079
 1330012231849    N330012231849        ...            0 6453800031849 20.2869
 1330012210212    N330012210212        ...            0 6453800010212 20.2767
>>> result.url
'http://gsss.stsci.edu/webservices/vo/ConeSearch.aspx?CAT=GSC23'

Get the number of matches and returned column names:

>>> len(result)
4028
>>> result.colnames
['objID',
 'gsc2ID',
 'gsc1ID',
 'hstID',
 'ra',
 'dec', ...,
 'Mag']

Extract RA and Dec of the matches:

>>> result_skycoord = SkyCoord(result['ra'], result['dec'])
>>> result_skycoord
<SkyCoord (ICRS): (ra, dec) in deg
    [(10.684737  , 41.269035  ), (10.683469  , 41.268585  ),
     (10.685657  , 41.26955   ), ..., (10.58375359, 41.33386612),
     (10.55860996, 41.30061722), (10.817729  , 41.26915741)]>

Using astroquery.vo_conesearch

This package has four main components across two categories:

• Using “Client” API
  • Catalog Manipulation
  • Database Manipulation
  • General VO Services Access
  • Simple Cone Search
• Using “Server” API
  • Validation for Simple Cone Search
  • Inspection of Validation Results

They are designed to be used in a work flow as illustrated below:

The one that a typical user needs is the Simple Cone Search component (see Cone Search Examples).

See Also

• Simple Cone Search Version 1.03, IVOA Recommendation (22 February 2008)

• STScI VAO Registry

• STScI VO Databases

Troubleshooting

If you are repeatedly getting failed queries, or bad/out-of-date results, try clearing your cache:

>>> from astroquery.vo_conesearch import ConeSearch
>>> ConeSearch.clear_cache()

If this function is unavailable, upgrade your version of astroquery. The clear_cache function was introduced in version 0.4.7.dev8479.

Reference/API

astroquery.vo_conesearch.core Module

Classes

ConeSearchClass()

The class for querying the Virtual Observatory (VO) Cone Search web service.

Class Inheritance Diagram

astroquery.vo_conesearch.vos_catalog Module

Common utilities for accessing VO simple services.

Note

Some functions are not used by Astroquery but kept for backward-compatibility with astropy.vo.client.

Functions

get_remote_catalog_db(dbname, *[, cache, ...])	Get a database of VO services (which is a JSON file) from a remote location.
call_vo_service(service_type[, catalog_db, ...])	Makes a generic VO service call.
list_catalogs(service_type[, cache, verbose])	List the catalogs available for the given service type.

Classes

VOSBase(tree)	Base class for VO catalog and database.
VOSCatalog(tree)	A class to represent VO Service Catalog.
VOSDatabase(tree)	A class to represent a collection of VOSCatalog.

astroquery.vo_conesearch.conesearch Module

Support VO Simple Cone Search capabilities.

Functions

conesearch(center, radius, *[, verb, ...])	Perform Cone Search and returns the result of the first successful query.
search_all(*args, **kwargs)	Perform Cone Search and returns the results of all successful queries.
list_catalogs(**kwargs)	Return the available Cone Search catalogs as a list of strings.
predict_search(url, *args, **kwargs)	Predict the run time needed and the number of objects for a Cone Search for the given access URL, position, and radius.
conesearch_timer(*args, **kwargs)	Time a single Cone Search using astroquery.utils.timer.timefunc with a single try and a verbose timer.

Classes

AsyncConeSearch(*args, **kwargs)	Perform a Cone Search asynchronously and returns the result of the first successful query.
AsyncSearchAll(*args, **kwargs)	Perform a Cone Search asynchronously, storing all results instead of just the result from first successful query.

astroquery.vo_conesearch.vo_async Module

Asynchronous VO service requests.

Classes

AsyncBase(func, *args, **kwargs)

Base class for asynchronous VO service requests using concurrent.futures.ThreadPoolExecutor.

astroquery.vo_conesearch.exceptions Module

Exceptions related to Virtual Observatory (VO).

Classes

BaseVOError	Base class for VO exceptions.
VOSError	General VO service exception.
MissingCatalog	VO catalog is missing.
DuplicateCatalogName	VO catalog of the same title already exists.
DuplicateCatalogURL	VO catalog of the same access URL already exists.
InvalidAccessURL	Invalid access URL.
ConeSearchError	General Cone Search exception.

Class Inheritance Diagram

astroquery.vo_conesearch.validator.validate Module

Validate VO Services.

Functions

check_conesearch_sites(*[, destdir, ...])

Validate Cone Search Services.

astroquery.vo_conesearch.validator.inspect Module

Inspect results from astroquery.vo_conesearch.validator.validate().

Classes

ConeSearchResults(*[, cache, verbose])

A class to store Cone Search validation results.

astroquery.vo_conesearch.validator.exceptions Module

Exceptions related to Virtual Observatory (VO) validation.

Classes

BaseVOValidationError	Base class for VO validation exceptions.
ValidationMultiprocessingError	Validation using multiprocessing failed.

Class Inheritance Diagram