uvcal_parameters.rst
UVCal Parameters
==============
These are the standard attributes of UVCal objects.
Under the hood they are actually properties based on UVParameter objects.
Required
----------------
These parameters are required to have a sensible UVCal object and
are required for most kinds of uv cal files.
**Nants_data**
Number of antennas with data present (i.e. number of unique entries in ant_1_array and ant_2_array). May be smaller than the number of antennas in the array
**Nants_telescope**
Number of antennas in the array. May be larger than the number of antennas with data
**Nfreqs**
Number of frequency channels
**Njones**
Number of polarizations calibrationparameters (Number of jones matrix elements.).
**Nspws**
Number of spectral windows (ie non-contiguous spectral chunks). More than one spectral window is not currently supported.
**Ntimes**
Number of times
**antenna_names**
List of antenna names, shape (Nants_telescope), with numbers given by antenna_numbers (which can be matched to ant_1_array and ant_2_array). There must be one entry here for each unique entry in ant_1_array and ant_2_array, but there may be extras as well.
**antenna_numbers**
List of integer antenna numbers corresponding to antenna_names,shape (Nants_telescope). There must be one entry here for each unique entry in ant_1_array and ant_2_array, but there may be extras as well.
**cal_type**
cal type parameter. Values are delay, gain or unknown.
**channel_width**
Channel width of of a frequency bin. Units Hz.
**flag_array**
Array of flags to be applied to calibrated data (logical OR of input and flag generated by calibration). True is flagged.shape: (Nants_data, Nfreqs, Ntimes, Njones), type = bool.
**freq_array**
Array of frequencies, shape (Nspws, Nfreqs), units Hz
**freq_range**
('Frequency range that gain solutions are valid for.', 'list: (start_frequency, end_frequency) in Hz.')
**gain_convention**
The convention for applying he calibration solutions to data.Indicates that to calibrate one should divide or multiply uncalibrated data by gains.
**history**
String of history, units English
**integration_time**
Integration time of a time bin (s).
**jones_array**
Array of antenna polarization integers, shape (Njones). linear pols -5:-8 (jxx, jyy, jxy, jyx).circular pols -1:-4 (jrr, jll. jrl, jlr).
**quality_array**
Array of qualities of calibration solutions shape: (Nants_data, Nfreqs, Ntimes, Njones), type = float.
**telescope_name**
Name of telescope. e.g. HERA. String.
**time_array**
Array of times, center of integration, shape (Ntimes), units Julian Date
**time_range**
('Time range (in JD) that gain solutions are valid for.', 'list: (start_time, end_time) in JD.')
**x_orientation**
Orientation of the physical dipole corresponding to what is labelled as the x polarization. Values are east (east/west orientation), north (north/south orientation) or unknown.
Optional
----------------
These parameters are defined by one or more file standard but are not always required.
Some of them are required depending on the cal_type (as noted below).
**delay_array**
Array of delays. shape: (Nants_data, Ntimes, Njones), type = float
**gain_array**
Array of gains, shape: (Nants_data, Nfreqs, Ntimes, Njones), type = complex float.
**git_hash_cal**
Commit hash of calibration software(from git_origin_cal) usedto generate solutions.
**git_origin_cal**
Origin (on github for e.g) of calibration software. Url and branch.
**input_flag_array**
Array of input flags, True is flagged. shape: (Nants_data, Nfreqs, Ntimes, Njones), type = bool.
**observer**
Name of observer who calculated solutions in this file.
last updated: 2017-04-05