ska_ost_senscalc.mid_utilities
Module holding functions useful to the MidCalculator
- class ska_ost_senscalc.mid_utilities.Beam(*, frequency=None, zoom_frequencies=None, array_configuration, weighting, robustness=None, dec, taper=0.0, calculator_mode, telescope=Telescope.MID)[source]
Beam class
- Parameters:
frequency (astropy.units.Quantity or number) – the observing frequency (Hz)
zoom_frequencies (iterable astropy.units.Quantity or list) – the frequencies of the line zooms (Hz)
array_configuration (ArrayConfiguration) – the subarray configuration
weighting (Weighting) – the type of uv-weighting used (robust or uniform)
robustness (float) – the Briggs robustness parameter
dec (astropy.units.Quantity or number) – the target declination (deg)
taper (astropy.units.Quantity or number) – the Gaussian taper to apply (arcsec)
calculator_mode (CalculatorMode) – the calculator mode being used
- Returns:
Beam object
- Return type:
- class ska_ost_senscalc.mid_utilities.BeamSize(beam_maj, beam_min, beam_pa)[source]
Class for returning a BeamSize object.
- Parameters:
beam_maj (astropy.units.Quantity or number) – the beam major axis in degrees
beam_min (astropy.units.Quantity or number) – the beam minor axis in degrees
beam_pa (astropy.units.Quantity or number) – the beam position angle in degrees
- Returns:
BeamSize object
- Return type:
- class ska_ost_senscalc.mid_utilities.CalculatorMode(value)[source]
Enumeration for calculator modes
- ska_ost_senscalc.mid_utilities.Tgal(target, obs_freq, dish_type, alpha)[source]
Brightness temperature of Galactic background in target direction at observing frequency.
- ska_ost_senscalc.mid_utilities.Trcv(obs_freq, obs_band, dish_type)[source]
Receiver temperature for specified freq, band and dish.
- ska_ost_senscalc.mid_utilities.Tsky(Tgal, obs_freq, elevation, weather)[source]
Brightness temperature of sky in target direction.
- Parameters:
Tgal (astropy.units.Quantity) – brightness temperature of Galactic background
obs_freq (astropy.units.Quantity) – the observing frequency
elevation (astropy.units.Quantity) – the observing elevation
weather (float) – the atmosphere PWV
- Returns:
the brightness temperature of the sky
- Return type:
astropy.units.Quantity
- ska_ost_senscalc.mid_utilities.Tspl(dish_type)[source]
Spillover temperature for specified dish type.
- Parameters:
dish_type (DishType) – the type of dish
- Returns:
the spillover temperature
- Return type:
astropy.units.Quantity
- ska_ost_senscalc.mid_utilities.Tsys_dish(Trcv, Tspl, Tsky, obs_freq)[source]
System temperature.
- Parameters:
Trcv (astropy.units.Quantity) – the receiver temperature
Tspl (astropy.units.Quantity) – the spillover temperature
Tsky (astropy.units.Quantity) – the sky temperature
obs_freq (astropy.units.Quantity) – the observing frequency
- Returns:
the dish system temperature
- Return type:
astropy.units.Quantity
- ska_ost_senscalc.mid_utilities.eta_bandpass()[source]
Efficiency factor for due to the departure of the bandpass from an ideal, rectangular shape. For now this is a placeholder.
- Returns:
the efficiency, eta
- Return type:
- ska_ost_senscalc.mid_utilities.eta_coherence(obs_freq)[source]
Efficiency factor for the sensitivity degradation due to the incoherence on a baseline.
- Parameters:
obs_freq (astropy.units.Quantity) – the observing frequency
- Returns:
the efficiency, eta
- Return type:
- ska_ost_senscalc.mid_utilities.eta_correlation()[source]
Efficiency factor due to imperfection in the correlation algorithm, e.g. truncation error.
- Returns:
the efficiency, eta
- Return type:
- ska_ost_senscalc.mid_utilities.eta_digitisation(obs_band)[source]
Efficiency factor due to losses from quantisation during signal digitisation. This process is independent of the telescope and environment, but only depends on the ‘effective number of bits’ (ENOB) of the system, which depends in turn on digitiser quality and clock jitter, and on band flatness.
- ska_ost_senscalc.mid_utilities.eta_dish(obs_freq, dish_type)[source]
Efficiency factor due to losses for specified dish type.
- ska_ost_senscalc.mid_utilities.eta_point(obs_freq, dish_type)[source]
Efficiency factor at the observing frequency due to the dish pointing error.
- ska_ost_senscalc.mid_utilities.eta_rfi()[source]
Efficiency factor due to Radio Frequency Interference (RFI)
- Returns:
the efficiency, eta
- Return type:
- ska_ost_senscalc.mid_utilities.eta_system(eta_point, eta_coherence, eta_digitisation, eta_correlation, eta_bandpass)[source]
System efficiency for SKA interferometer
- Parameters:
eta_point (float) – efficiency loss due to pointing errors
eta_coherence (float) – efficiency due to loss of coherence
eta_digitisation (float) – efficiency loss due to errors in the digitisation process
eta_correlation (float) – efficiency loss due to errors in the correlation process
eta_bandpass (float) – efficiency loss due to the bandpass not being rectangular
- Returns:
the system efficiency
- Return type: