azely.object module#

Azely’s object module (mid-level API).

This module mainly provides Object class for information of an astronomical object (object information, hereafter) and get_object function to search for object information as an instance of Object class.

The Object class is defined as Object(name: str, frame: str, longitude: str, latitude: str), where frame is a name of equatorial coordinates (e.g., icrs) and lon/lat are values of coordinates which must be written with units like 02h42m40.771s/-00d00m47.84s.

The get_object function acquires object information from: (1) Data from CDS (by default). Internet connection is required. (2) User-defined object information written in a TOML file.

In the case of (1), obtained object information is cached in a special TOML file (~/.config/azely/objects.toml) for an offline use.

In the case of (2), users can define object information in a TOML file (e.g., user.toml) which should be put in a current directory or in the Azely’s config directory (~/.config/azely). Object information must be defined as a table in the TOML file like:

# user.toml

[GC]
name = "Galactic center"
frame = "galactic"
longitude = "0deg"
latitude = "0deg"

Then object information can be obtained by get_object(<query>). Use get_object(<name>:<query>) for user-defined object information, where <name> must be the name of a TOML file without suffix or the full path of it. If it does not exist in a current directory, the function will try to find it in the Azely’s config directory (~/.config/azely).

Examples

To get object info from CDS:

>>> obj = azely.object.get_object('NGC1068')

To get object info from user.toml:

>>> obj = azely.object.get_object('user:GC')
class Object(name: str, frame: str, longitude: str, latitude: str)[source]#

Bases: object

Azely’s object information class.

Parameters:

  • name (str) –

  • frame (str) –

  • longitude (str) –

  • latitude (str) –

frame: str#

Name of equatorial coordinates.

is_solar() → bool[source]#

Return True if it is an solar object.

Return type:

bool

latitude: str#

Latitude (e.g., dec or b) with units.

longitude: str#

Longitude (e.g., ra or l) with units.

name: str#

Object’s name.

to_dict() → Dict[str, str][source]#

Convert it to a Python’s dictionary.

Return type:

Dict[str, str]

to_skycoord(obstime: Time) → SkyCoord[source]#

Convert it to an astropy’s skycoord with given obstime.

Parameters:

obstime (Time) –

Return type:

SkyCoord

get_object(query: str, frame: str = 'icrs', timeout: int = 10) → Object[source]#

Get object information by various ways.

This function acquires object information by the following two ways: (1) Data from CDS (by default). Internet connection is required. (2) User-defined object information written in a TOML file.

In the case of (1), obtained object information is cached in a special TOML file (~/.config/azely/objects.toml) for an offline use.

In the case of (2), users can define object information in a TOML file (e.g., user.toml) which should be put in a current directory or in the Azely’s config directory (~/.config/azely).

Then object information can be obtained by get_object(<query>). Use get_object(<name>:<query>) for user-defined object information, where <name> must be the name of a TOML file without suffix or the full path of it. If it does not exist in a current directory, the function will try to find it in the Azely’s config directory (~/.config/azely).

Parameters:

  • query (str) – Query string (e.g., 'NGC1068' or 'user:GC').

  • frame (str) – Name of equatorial coordinates used in astropy’s SkyCoord.

  • timeout (int) – Query timeout expressed in units of seconds.

Returns:

Object information as an instance of Object class.

Raises:

AzelyError – Raised if the function fails to get object information.

Return type:

Object

Notes

As object is the Python’s builtin base class, it might be better to use an alternative variable name (e.g., object_ or obj) for object information which this function returns.

Examples

To get object info from CDS:

>>> obj = azely.object.get_object('NGC1068')

To get object info from user.toml:

>>> obj = azely.object.get_object('user:GC')