ska_oso_pdm.entities.common.target
The target module models entities concerned with receptor pointing and mapping (source coordinates, survey fields, pointing patterns, etc.). The contents of the module are presented in the diagram below.
Class diagram for the target module
An example serialisation of this model to JSON is shown below. This describes two target objects: one, a five-point observation centred on Polaris Australis using 5 arcsec offsets between individual pointings, and two, a single pointing observation centred on M83. In both cases, the coordinates are defined using equatorial coordinates using an ICRS reference frame.
# JSON modelled specifically by target module
...
"targets": [
{
"target_id": "Polaris Australis",
"pointing_pattern": {
"active": "FivePointParameters",
"parameters": [
{
"kind": "FivePointParameters",
"offset_arcsec": 5.0
}
]
},
"reference_coordinate": {
"kind": "equatorial",
"ra": "21:08:47.92",
"dec": "-88:57:22.9",
"reference_frame": "ICRS",
"unit": ["hourangle","deg"]
}
},
{
"target_id": "M83",
"pointing_pattern": {
"active": "SinglePointParameters",
"parameters": [
{
"kind": "SinglePointParameters",
"offset_x_arcsec": 0.0,
"offset_y_arcsec": 0.0
}
]
},
"reference_coordinate": {
"kind": "equatorial",
"ra": "13:37:00.919",
"dec": "-29:51:56.74",
"reference_frame": "ICRS",
"unit": ["hourangle","deg"]
}
}
],
...
Another JSON example defining one drift scan target with position specified as azimuth and elevation is shown below.
...
"targets": [
{
"target_id": "target #1",
"pointing_pattern": {
"active": "SinglePointParameters",
"parameters": [
{
"kind": "SinglePointParameters",
"offset_x_arcsec": 0.0,
"offset_y_arcsec": 0.0
}
]
},
"reference_coordinate": {
"kind": "horizontal",
"az": 180.0,
"el": 45.0,
"reference_frame": "ALTAZ",
"unit": ["hourangle","deg"]
}
}
],
...
The entities.common.target module defines a Python representation of the target of the observation.