These are the standard attributes of UVCal objects.
Under the hood they are actually properties based on UVParameter objects.
These parameters are required to have a sensible UVCal object and are required for most kinds of uv cal files.
Number of antennas that have data associated with them (i.e. length of ant_array), which may be smaller than the numberof antennas in the telescope (i.e. length of antenna_numbers).
Number of antennas in the antenna_numbers array. May be larger than the number of antennas with gains associated with them.
Number of frequency channels
Number of Jones calibrationparameters (Number of Jones matrix elements calculated in calibration).
Number of spectral windows (ie non-contiguous spectral chunks). More than one spectral window is not currently supported.
Number of times with different calibrations calculated (if a calibration is calculated over a range of integrations, this gives the number of separate calibrations along the time axis).
Array of integer antenna numbers that appear in self.gain_array, with shape (Nants_data,). This array is ordered to match the inherent ordering of the zeroth axis of self.gain_array.
Array of antenna names with shape (Nants_telescope,). Ordering of elements matches ordering of antenna_numbers.
Array of all integer-valued antenna numbers in the telescope with shape (Nants_telescope,). Ordering of elements matches that of antenna_names. This array is not necessarily identical to ant_array, in that this array holds all antenna numbers associated with the telescope, not just antennas with data, and has an in principle non-specific ordering.
Style of calibration. Values are sky or redundant.
cal type parameter. Values are delay, gain or unknown.
Channel width of of a frequency bin. Units Hz.
Array of frequencies, center of the channel, shape (Nspws, Nfreqs), units Hz.
The convention for applying the calibration solutions to data.Values are “divide” or “multiply”, indicating that to calibrate one should divide or multiply uncalibrated data by gains. Mathematically this indicates the alpha exponent in the equation: calibrated data = gain^alpha * uncalibrated data. A value of “divide” represents alpha=-1 and “multiply” represents alpha=1.
String of history, units English
Integration time of a time bin, units seconds.
Array of antenna polarization integers, shape (Njones). linear pols -5:-8 (jxx, jyy, jxy, jyx).circular pols -1:-4 (jrr, jll. jrl, jlr).
Array of spectral window numbers, shape (Nspws).
Name of telescope. e.g. HERA. String.
Array of calibration solution times, center of integration, shape (Ntimes), units Julian Date
Orientation of the physical dipole corresponding to what is labelled as the x polarization. Options are “east” (indicating east/west orientation) and “north” (indicating north/south orientation)
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).
Number of sources used.
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.
Range of baselines used for calibration.
Required if cal_type = “delay”. Array of delays with units of seconds. Shape: (Nants_data, Nspws, 1, Ntimes, Njones), type = float.
Name of diffuse model.
Any user supplied extra keywords, type=dict. Keys should be 8 character or less strings if writing to calfits files. Use the special key “comment” for long multi-line string comments.
Array of flags to be applied to calibrated data (logical OR of input and flag generated by calibration). True is flagged. Shape: (Nants_data, Nspws, Nfreqs, Ntimes, Njones), type = bool.
Required if cal_type = ‘delay’. Frequency range that solutions are valid for. list: [start_frequency, end_frequency] in Hz.
Required if cal_type = “gain”. Array of gains, shape: (Nants_data, Nspws, Nfreqs, Ntimes, Njones), type = complex float.
The gain scale of the calibration, which indicates the units of the calibrated visibilities. For example, Jy or K str.
Commit hash of calibration software (from git_origin_cal) used to generate solutions.
Origin (on github for e.g) of calibration software. Url and branch.
Array of input flags, True is flagged. shape: (Nants_data, Nspws, Nfreqs, Ntimes, Njones), type = bool.
Array of lsts, center of integration, shape (Ntimes), units radians
Name of observer who calculated solutions in this file.
Array of qualities of calibration solutions. The shape depends on cal_type, if the cal_type is ‘gain’ or ‘unknown’, the shape is: (Nants_data, Nspws, Nfreqs, Ntimes, Njones), if the cal_type is ‘delay’, the shape is (Nants_data, Nspws, 1, Ntimes, Njones). The type is float.
Required if cal_style = “sky”. Phase reference antenna.
Required if cal_style = “sky”. Name of calibration catalog.
Required if cal_style = “sky”. Short string describing field center or dominant source.
Telescope location: xyz in ITRF (earth-centered frame). Can also be accessed using telescope_location_lat_lon_alt or telescope_location_lat_lon_alt_degrees properties
Time range (in JD) that cal solutions are valid for.list: [start_time, end_time] in JD. Should only be set in Ntimes is 1.
Array of qualities of the calibration for entire arrays. The shape depends on cal_type, if the cal_type is “gain” or “unknown”, the shape is: (Nspws, Nfreqs, Ntimes, Njones), if the cal_type is “delay”, the shape is (Nspws, 1, Ntimes, Njones), type = float.
last updated: 2021-10-21