ChebyValues

class rubin_sim.moving_objects.ChebyValues

Bases: object

Calculates positions, velocities, deltas, vmags and elongations, given a series of coefficients generated by ChebyFits.

Methods Summary

get_ephemerides(times[, obj_ids, extrapolate])	Find the ephemeris information for 'obj_ids' at 'time'.
read_coefficients(cheby_fits_file)	Read coefficients from output file written by ChebyFits.
set_coefficients(cheby_fits)	Set coefficients using a ChebyFits object.

Methods Documentation

get_ephemerides(times, obj_ids=None, extrapolate=False)

Find the ephemeris information for ‘obj_ids’ at ‘time’.

Implicit in how this is currently written is that the segments are all expected to cover the same start/end time range across all objects. They do not have to have the same segment length for all objects.

Parameters:

timesfloat or np.ndarray

The time to calculate ephemeris positions.

obj_idsnp.ndarray, opt

The object ids for which to generate ephemerides. If None, then just uses all objects.

extrapolatebool, opt

If True, extrapolate beyond ends of segments if time outside of segment range. If False, return ValueError if time is beyond range of segments.

Returns:

ephemeridesnp.ndarray

The ephemeris positions for all objects. Note that these may not be sorted in the same order as obj_ids.

read_coefficients(cheby_fits_file)

Read coefficients from output file written by ChebyFits.

Parameters:

cheby_fits_filestr

The filename of the coefficients file.

set_coefficients(cheby_fits)

Set coefficients using a ChebyFits object. (which contains a dictionary of obj_id, t_start, t_end, ra, dec, delta, vmag, and elongation lists).

Parameters:

cheby_fitsrubin_sim.movingObjects.chebyFits

ChebyFits object, with attribute ‘coeffs’ - a dictionary of lists of coefficients.