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| I have implemented part of the `astroquery` module to easily make simulations of objects on the JPL Horizons System, using `GET`/`POST` URL encoded requests. I have restricted the inputs to standardise the output for use in this project, but you should be able to get any body listed on the JPL Horizons System fairly easily. | ||
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| > [!NOTE] | ||
| > The content on this page is unlikely to change and is stable. | ||
| ## `horizons_query()` | ||
| Returns attributes from a single search query, i.e, 'Sun'. | ||
| ### Parameters | ||
| * `searchquery` (`str`) - object ID or identifiable name of object, ie, `'Sun'`. | ||
| * `observer` (`str`) - observer position ID. see JPL Horizons Manual for more info, default is `'0'` (Sun/Solar System Barycentric Centre). It is best to make this the reference object of your system. | ||
| * `time` (`str`) - time to get data from. **Note: You should keep this the same for all objects in a system.** format is in MJY (YYYY-MM-DD). | ||
| * `num_type` (`type`) - type of numerical to output information in, if needing high accuracy. Default is `float`. | ||
| * `return_type` (`str`) how to output the result, either as a `dict` (`'dict'`), `Body` (`'body'`) or printing the result (`'print'`). | ||
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| > [!TIP] | ||
| >In the case that the `searchquery` returns multiple unique objects, a list of objects should be outputted where you should enter the ID of your chosen object into the function instead. | ||
| ### Returns | ||
| * This function will return a `Body` instance with the attributes of the queried object by default. | ||
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| ## `horizons_batch()` | ||
| `horizons_batch` is a function that makes it easy to iterate over multiple objects using the same constants and return an iterable containing the result. Has the exact same arguments as `horizons_query()` except the input queries should be an iterable of `str` objects. | ||
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| ## Examples: | ||
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| ### Create an list of `Body` instances representing all the major bodies in the solar system. | ||
| ```python | ||
| bodies = list(horizons_query(obj_id) for obj_id in ( | ||
| '10','199','299','399','499','599','699','799','899')) | ||
| ``` | ||
| > [!TIP] | ||
| >this could actually be made more concise: | ||
| >```python | ||
| >bodies = horizons_batch(['10','199','299','399','499','599','699','799','899']) | ||
| >``` | ||
| >```python | ||
| >print(bodies) | ||
| >``` | ||
| Returns: | ||
| >``` | ||
| >Querying "10" @JPL Horizons System | ||
| > ... | ||
| >Querying "899" @JPL Horizons System | ||
| >Getting data from JPL Horizons: 100%|█████████████████████████████████████████████████████████████████████████████| 9/9 [00:00<00:00, 98.66queries/s] | ||
| >[Body("Sun (10)", m=1.9885e+30, r=(...),v=(...)), a=(0, 0, 0)), | ||
| > ... | ||
| >Body("Neptune (899)", m=1.02409e+26, r=(...),v=(...)), a=(0, 0, 0))] | ||
| >``` | ||
| ### Printing attributes of a body as `Decimal` and Querying using text: | ||
| > running this: would give us an error, | ||
| >```python | ||
| >from decimal import Decimal | ||
| >horizons_query('Pluto', num_type=Decimal, return_type='print') | ||
| >``` | ||
| >Returns: | ||
| >``` | ||
| >Querying "Pluto" @JPL Horizons System | ||
| >Traceback (most recent call last): | ||
| > ... | ||
| >ValueError: Ambiguous target name; provide unique id: | ||
| > ID# Name Designation IAU/aliases/other | ||
| > ------- ---------------------------------- ----------- ------------------- | ||
| > 9 Pluto Barycenter | ||
| > 999 Pluto 134340 | ||
| >``` | ||
| > The error is given as the horizons server picked up two possible objects that it could query, and cannot work out which one you wanted. | ||
| >instead, after the error we can choose the correct ID for the body we want to return, i.e, 999. | ||
| >```python | ||
| >horizons_query('999', num_type=Decimal, return_type='print') | ||
| >``` | ||
| >Returns: | ||
| >``` | ||
| >Querying "999" @JPL Horizons System | ||
| >Object: Pluto (999) | ||
| >*********** | ||
| >Mass: 13070000000000000000000.000 kg | ||
| >Radius: 1188300.0 m | ||
| >*********** | ||
| >position: (2436011869867.81494140625, -4641552098041.7890625, -250706318802.340087890625) (m) | ||
| >velocity: (24682.81863152435471420176327228546142578125, -21445.24496392483706586062908172607421875, -1503.5218150639748273533768951892852783203125)(ms^-1) | ||
| >*********** | ||
| >Query Date: 2023-11-03 | ||
| >``` | ||
| > [!IMPORTANT] | ||
| > If you were to choose ''Pluto Barycenter'`, this would raise an exception as the function would not be able to find the mass or radius as a barycenter is not a physical object. |