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- NEODyS Queries (`astroquery.solarsystem.neodys`)

# NEODyS Queries (`astroquery.solarsystem.neodys`)

## Getting started

This module supports retrieving the orbital information of an object from the NEODyS website (https://newton.spacedys.com/neodys/). The state vector, covariance matrix, epoch, absolute magnitude, slope parameter, and correlation matrix are given in dictionary form. The results can be given in either Keplerian or Equinoctial. The only required argument is the identifier of the object to be retrieved. Here is a basic example:

    >>> from astroquery.solarsystem.neodys import NEODyS
    >>> result = NEODyS.query_object("1982YA")
    >>> print(result)
    {'Equinoctial State Vector': [3.6501814973859177, 0.55510840531515, 0.412442615432626, -0.316403600209491, -0.005615261288851, 7.4974723045741],
    'Mean Julian Date': ['57672.370442276', 'TDT'],
    'Magnitude': [17.478, 0.15],
    'Covariance Matrix': [2.983481961445874e-14, 1.319692615237118e-13, -3.466482497808619e-13,
                          -5.179294501167426e-15, 4.40306644125416e-15, 2.841155344781695e-11,
                          7.248099966950092e-13, -1.55363923471562e-12, -4.018099391315557e-14,
                          -1.400231787484278e-14, 1.210874090734312e-10, 4.091233073364273e-12,
                          4.62498475268648e-15, -1.406987981569261e-14, -3.37147537859451e-10,
                          6.527443331995206e-13, -4.021096836415107e-13, -3.876453730470366e-12,
                          3.584924689571663e-13, 8.057672786144392e-12, 2.841126641896583e-08],
    'Keplerian Correlation Matrix': [],
    'URL': 'https://newton.spacedys.com/~neodys2/epoch//1982YA.eq0'}

### More detailed parameters

There are two other optional parameters that can be specified. These are `orbital_element_type` which specifies whether the results will be in Keplerian or Equinoctial. Valid values are ‘ke’ for Keplerian and ‘eq’ for Equinoctial. The other is `epoch_near_present`, a flag which sets the epoc to near present instead of near middle of the arc. Valid values are ‘0’ for near middle of the arc, and ‘1’ for near present. The default values are ‘eq’ and ‘0’. Note: Keplerian elements are given to a lower precision on the NEODyS website.

Here’s an example with these optional parameters:

    >>> from astroquery.solarsystem.neodys import NEODyS
    >>> results = NEODyS.query_object("1982YA", orbital_element_type="ke", epoch_near_present=1)
    >>> print(results)
    {'Keplerian State Vector': [3.64669, 0.691945, 35.165, 268.935, 144.408, 283.498],
    'Mean Julian Date': ['60000.0000', 'TDT'],
    'Magnitude': [17.478, 0.15],
    'Covariance Matrix': [3.92261704e-14, -1.16359258e-13, 3.11585918e-13,
                          5.00974344e-13, 3.35974943e-11, -6.24946297e-12,
                          4.44803944e-13, 3.19086108e-12, -3.60667109e-12,
                          -9.43905769e-11, 6.70717262e-12, 6.92715199e-09,
                          7.66896347e-09, -7.46695141e-09, 1.41600249e-10,
                          1.22064798e-08, -1.21318576e-08, 1.39344281e-09,
                          4.21853471e-08, -7.19870851e-09, 2.62151264e-09],
    'Keplerian Correlation Matrix': [1.0, -0.88090418, 0.01890221,
                                     0.02289456, 0.82592026, -0.61628098,
                                     1.0, 0.0574839, -0.0489471,
                                     -0.68907027, 0.19641705, 1.0,
                                     0.83399624, -0.43680254, 0.0332285,
                                     1.0, -0.53462747, 0.24633037,
                                     1.0, -0.68453837, 1.0],
    'URL': 'https://newton.spacedys.com/~neodys2/epoch//1982YA.ke1'}

## Reference/API

### astroquery.solarsystem.neodys Package

#### NEODyS Query Tool

Author:

  B612 Foundation

This package is for querying NEODys website

#### Classes

`NEODySClass`() |
`Conf`() | Configuration parameters for `astroquery.solarsystem.neodys`.