planetTemperature

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Estimates the expected ALMA 12m antenna temperature when observing a planet, based on its model radiative temperature in CASA. It is up to the user to enter the correct antenna efficiency. See also planet and planetFlux.

Usage:

au.planetTemperature(body=None, frequency=None, angularDiameter=None, vis=None, date='', 
                 intent='OBSERVE_TARGET#ON_SOURCE', efficiency=None, spw=None, beamFwhm=None, 
                 beamFwhmFactor=1.13, telescopeDiameter=12, useJPL=True, surfaceRms=25, temperature=None)
  • planet: one of /usr/lib64/casapy/data/alma/SolarSystemModels/*_Tb.dat (currently: 'CALLISTO','CERES','EUROPA','GANYMEDE','IO', 'JUNO','JUPITER','MARS','NEPTUNE','PALLAS','TITAN', 'URANUS','VENUS','VESTA')
  • frequency: observed frequency (Hz, GHz, or a string with units)
  • angularDiameter: of body in arcsec
  • vis: measurement set to consult for planet name, date, frequency and/or angular diameter (in case any of those values are not given)
  • date: date of observation (format same as au.planet)
  • efficiency: antenna efficiency on scale of 0..1, if None, then use antennaEfficiency(surfaceRms)
  • spw: the spw to use if vis is specified
  • beamFwhm: the beamsize to use instead of 1.13 lambda/D
  • beamFwhmFactor: the coefficient (C) to use in C*lambda/D
  • telescopeDiameter: telescope diameter (meters)
  • surfaceRms: in microns (only used of efficiency == None)
  • temperature: use the specified temperature, rather than CASA table

Examples:

CASA <27>: au.planetTemperature(frequency=85.07,body='Jupiter',angularDiameter=42.5)
Coefficient from Baars (2007) Eq 4.13 for a -9.9dB edge taper and obscuration ratio=0.75/12 = 1.130*lambda/D
telescope Gaussian beam FWHM at 85.1 GHz = 68.443 arcsec
coupling factor between 42.500 arcsec disk and Gaussian beam = 0.319947
antenna efficiency assumed = 0.750000
Jupiter model temperature = 161.490 K
expected brightness temperature = 38.751 K
  Out[27]: 38.751201156935565

CASA <2>: au.planetTemperature(vis='uid___A002_X70f4b6_X4e3.ms')
Got date from the first scan on Uranus (scan 6) using msmd
Got date from scan 6: 2013-10-30 06:07:09
Contacting JPL Horizons for URANUS
MJD= 56595.25497, MJDseconds= 4889830029.0, JD= 2456595.75497
Recognized observatory = ALMA
LST day = 63321,  LST = 4.1838 hours (at longitude=-67.754748)
Julian day = 2456595.754965, MJD = 56595.254965, MJD seconds = 4889830029.000000
Confirmed Target ID = 799 = Uranus
Range rate = +14.317328 km/sec
Azim = -70.850 deg   Elev = 31.535 deg
J2000 Position: 00:35:20.19295, +003:01:26.90760   Azim, Elev: -70.850, 31.535
J2000 Rate: -4.8319, -1.9795 arcsec/hour (position angle = -112.3deg)
J2000 Rate: -0.001342, -0.000550 arcsec/second  (position angle = -112.3deg)
Angular diameter (major axis) = 3.680015 arcsec
Angular diameter of URANUS = 3.680 arcsec
Coefficient from Baars (2007) Eq 4.13 for a -9.9dB edge taper and obscuration ratio=0.75/12 = 1.130*lambda/D
telescope Gaussian beam FWHM at 336.5 GHz = 17.303 arcsec
coupling factor between 3.680 arcsec disk and Gaussian beam = 0.044224
antenna efficiency assumed = 0.750000
URANUS model temperature = 87.500 K
expected brightness temperature = 2.902 K
  Out[2]: 2.9022100638447084

-- ToddHunter - 2013-11-08
Topic revision: r7 - 2014-08-21, ToddHunter
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