Query

This script is meant to give an example on how to use the the query-function of p2obt to get information on a target.

Note

The query function is based on a local catalog query (see Querying Local Catalogs) as well as a query of Vizier based catalogs (see Simple Query and Vizier Queries).

Simple Query

Queries the target ‘HD 142666’, and by default the following catalogs: ‘simbad’, ‘nomad’, ‘mdfc’, ‘gaia’, ‘tycho’, ‘2mass’ and ‘wise’. The catalogs can be either set manually with the ‘catalogs’ keyword or specific ones excluded with the ‘exclude_catalogs’ (both take a list as input). Further can the ‘match_radius’ be determined (in arcsec).

target = query("HD 142666")
print("Query with standard settings:")

Note

Some astronomical objects can have their object type as a prefix. p2obt takes care of that by automatically adding this prefix if the target can not be found in, for instance, simbad. For a comprehensive list see simbad object types.

Customization Options

There are various settings that enable a more user-tailored query. In the following, some examples of these are presented.

Note

For more information on the all the available settings see options.

Specifying accessed fields

The accessed fields can be modified with the OPTIONS SimpleNamespace (this also applies for the "catalog" and the "queries").

OPTIONS.catalogs.tycho.catalog = "..."
OPTIONS.catalogs.tycho.query = ["...", "..."]
OPTIONS.catalogs.tycho.fields = ["**"]

Query with excluded catalogs

Catalogs can also be excluded via the exclude_catalogs keyword.

target = query("HD 142666", exclude_catalogs=["tycho"])

Warning

This can result in errors if too many or all catalogs are excluded.

Querying Local Catalogs

There are also two local catalogs present in p2obt, which exists in order to provide either better/more accurate data on a target, or any data at all if the target is not listed in the online catalogs, or listed under another name.

Note

These are the catalogs "standard" and "ciao", which are separated, as there exists target overlaps with different values. (For more information on the local and all catalogs see options)

Warning

Be aware that not all targets of one catalog exist in the other. This can result in query errors, if the target is also not found in an online catalog.

The one queried by default is the "standard" catalog.

target = query("M8E-IR")

Changing the local catalog

In order to change the active local catalog, to, in this case, the one used for the CIAO Offaxis observations "ciao" one needs to change the following setting:

OPTIONS.catalogs.local.active = "ciao"

And now the target "YLW 16A, which is not present in the "standard" catalog can be queried.

target = query("YLW 16A")