Source code for pyuvdata.telescopes

# -*- mode: python; coding: utf-8 -*-
# Copyright (c) 2018 Radio Astronomy Software Group
# Licensed under the 2-clause BSD License

"""Telescope information and known telescope list."""
import os
import numpy as np
from astropy.coordinates import Angle, EarthLocation

from . import uvbase
from . import parameter as uvp
from import DATA_PATH

__all__ = ["Telescope", "known_telescopes", "get_telescope"]

# We use astropy sites for telescope locations. The dict below is for
# telescopes not in astropy sites, or to include extra information for a telescope.

# The center_xyz is the location of the telescope in ITRF (earth-centered frame)

# Antenna positions can be specified via a csv file with the following columns:
# "name" -- antenna name, "number" -- antenna number, "x", "y", "z" -- ECEF coordinates
# relative to the telescope location.
    "PAPER": {
        "center_xyz": None,
        "latitude": Angle("-30d43m17.5s").radian,
        "longitude": Angle("21d25m41.9s").radian,
        "altitude": 1073.0,
        "citation": (
            "value taken from capo/cals/, "
            "comment reads KAT/SA  (GPS), altitude from"
    "HERA": {
        "center_xyz": None,
        "latitude": Angle("-30.72152612068925d").radian,
        "longitude": Angle("21.42830382686301d").radian,
        "altitude": 1051.69,
        "diameters": 14.0,
        "antenna_positions_file": "hera_ant_pos.csv",
        "citation": (
            "value taken from hera_mc script "
            "(using hera_cm_db_updates under the hood.)"
    "SMA": {
        "center_xyz": None,
        "latitude": Angle("19d49m27.13895s").radian,
        "longitude": Angle("-155d28m39.08279s").radian,
        "altitude": 4083.948144,
        "citation": "Ho, P. T. P., Moran, J. M., & Lo, K. Y. 2004, ApJL, 616, L1",
    "SZA": {
        "center_xyz": None,
        "latitude": Angle("37d16m49.3698s").radian,
        "longitude": Angle("-118d08m29.9126s").radian,
        "altitude": 2400.0,
        "citation": "Unknown",
    "OVRO-LWA": {
        "center_xyz": None,
        "latitude": Angle("37.239777271d").radian,
        "longitude": Angle("-118.281666695d").radian,
        "altitude": 1183.48,
        "citation": "OVRO Sharepoint Documentation",

[docs]class Telescope(uvbase.UVBase): """ A class for defining a telescope for use with UVData objects. Attributes ---------- citation : str text giving source of telescope information telescope_name : UVParameter of str name of the telescope telescope_location : UVParameter of array_like telescope location xyz coordinates in ITRF (earth-centered frame). antenna_diameters : UVParameter of float Optional, antenna diameters in meters. Used by CASA to construct a default beam if no beam is supplied. """ def __init__(self): """Create a new Telescope object.""" # add the UVParameters to the class # use the same names as in UVData so they can be automatically set self.citation = None self._telescope_name = uvp.UVParameter( "telescope_name", description="name of telescope " "(string)", form="str" ) desc = ( "telescope location: xyz in ITRF (earth-centered frame). " "Can also be set using telescope_location_lat_lon_alt or " "telescope_location_lat_lon_alt_degrees properties" ) self._telescope_location = uvp.LocationParameter( "telescope_location", description=desc, acceptable_range=(6.35e6, 6.39e6), tols=1e-3, ) desc = ( "Antenna diameters in meters. Used by CASA to " "construct a default beam if no beam is supplied." ) self._antenna_diameters = uvp.UVParameter( "antenna_diameters", required=False, description=desc, expected_type=float, tols=1e-3, # 1 mm ) desc = "Number of antennas in the array." self._Nants_telescope = uvp.UVParameter( "Nants_telescope", required=False, description=desc, expected_type=int ) desc = ( "List of antenna names, shape (Nants_telescope), " "with numbers given by antenna_numbers." ) self._antenna_names = uvp.UVParameter( "antenna_names", required=False, description=desc, form=("Nants_telescope",), expected_type=str, ) desc = ( "List of integer antenna numbers corresponding to antenna_names, " "shape (Nants_telescope)." ) self._antenna_numbers = uvp.UVParameter( "antenna_numbers", required=False, description=desc, form=("Nants_telescope",), expected_type=int, ) desc = ( "Array giving coordinates of antennas relative to " "telescope_location (ITRF frame), shape (Nants_telescope, 3), " "units meters. See the tutorial page in the documentation " "for an example of how to convert this to topocentric frame." ) self._antenna_positions = uvp.UVParameter( "antenna_positions", required=False, description=desc, form=("Nants_telescope", 3), expected_type=float, tols=1e-3, # 1 mm ) super(Telescope, self).__init__()
[docs]def known_telescopes(): """ Get list of known telescopes. Returns ------- list of str List of known telescope names. """ astropy_sites = EarthLocation.get_site_names() while "" in astropy_sites: astropy_sites.remove("") known_telescopes = list(set(astropy_sites + list(KNOWN_TELESCOPES.keys()))) return known_telescopes
def _parse_antpos_file(antenna_positions_file): """ Interpret the antenna positions file. Parameters ---------- antenna_positions_file : str Name of the antenna_positions_file, which is assumed to be in DATA_PATH. Should contain antenna names, numbers and ECEF positions relative to the telescope location. Returns ------- antenna_names : array of str Antenna names. antenna_names : array of int Antenna numbers. antenna_positions : array of float Antenna positions in ECEF relative to the telescope location. """ columns = ["name", "number", "x", "y", "z"] formats = ["U10", "i8", np.longdouble, np.longdouble, np.longdouble] dt = np.format_parser(formats, columns, []) ant_array = np.genfromtxt( antenna_positions_file, delimiter=",", autostrip=True, skip_header=1, dtype=dt.dtype, ) antenna_names = ant_array["name"] antenna_numbers = ant_array["number"] antenna_positions = np.stack((ant_array["x"], ant_array["y"], ant_array["z"])).T return antenna_names, antenna_numbers, antenna_positions.astype("float")
[docs]def get_telescope(telescope_name, telescope_dict_in=None): """ Get Telescope object for a telescope in telescope_dict. Parameters ---------- telescope_name : str Name of a telescope telescope_dict_in: dict telescope info dict. Default is None, meaning use KNOWN_TELESCOPES (other values are only used for testing) Returns ------- Telescope object The Telescope object associated with telescope_name. """ if telescope_dict_in is None: telescope_dict_in = KNOWN_TELESCOPES astropy_sites = EarthLocation.get_site_names() telescope_keys = list(telescope_dict_in.keys()) telescope_list = [tel.lower() for tel in telescope_keys] if telescope_name in astropy_sites: telescope_loc = EarthLocation.of_site(telescope_name) obj = Telescope() obj.telescope_name = telescope_name obj.citation = "astropy sites" obj.telescope_location = np.array( [telescope_loc.x.value, telescope_loc.y.value, telescope_loc.z.value] ) elif telescope_name.lower() in telescope_list: telescope_index = telescope_list.index(telescope_name.lower()) telescope_dict = telescope_dict_in[telescope_keys[telescope_index]] obj = Telescope() obj.citation = telescope_dict["citation"] obj.telescope_name = telescope_keys[telescope_index] if telescope_dict["center_xyz"] is not None: obj.telescope_location = telescope_dict["center_xyz"] else: if ( telescope_dict["latitude"] is None or telescope_dict["longitude"] is None or telescope_dict["altitude"] is None ): raise ValueError( "either the center_xyz or the " "latitude, longitude and altitude of the " "telescope must be specified" ) obj.telescope_location_lat_lon_alt = ( telescope_dict["latitude"], telescope_dict["longitude"], telescope_dict["altitude"], ) else: # no telescope matching this name return False # check for extra info if telescope_name.lower() in telescope_list: telescope_index = telescope_list.index(telescope_name.lower()) telescope_dict = telescope_dict_in[telescope_keys[telescope_index]] if "diameters" in telescope_dict.keys(): obj.antenna_diameters = telescope_dict["diameters"] if "antenna_positions_file" in telescope_dict.keys(): antpos_file = os.path.join( DATA_PATH, telescope_dict["antenna_positions_file"] ) antenna_names, antenna_numbers, antenna_positions = _parse_antpos_file( antpos_file ) obj.Nants_telescope = antenna_names.size obj.antenna_names = antenna_names obj.antenna_numbers = antenna_numbers obj.antenna_positions = antenna_positions obj.check(run_check_acceptability=True) return obj