Basic Information on obsrms

Task: obsrms
Purpose: Calculate theoretical rms for telescope array observations.
Categories: image analysis

        OBSRMS - Calculate theoretical rms for telescope array observations.
        The MIRIAD task TELEPAR provides typical values for Tsys and Jy/K.
        for several observatories.

Key: tsys
        SSB system temperature (Kelvin). Default=300 K.
        Tsys includes the loss through the atmosphere.

Key: jyperk
        Antenna gain in units Jy/K. Default=150 Jy/K.

Key: antdiam
        Antenna diameter (m), and aperture efficiency can be used to calculate
        jyperk. If only one value is given then the aperture efficiency used
        is 0.6. Default=0,0.6 i.e. use jyperk value.

Key: lambda
        wavelength in millimeters. Default=3 mm.

Key: freq
        freq (GHz) can be used to compute lambda. Default=0 GHz, uses lambda.

Key: theta
        Beamsize in arcsec. Two values may be given for the beam FWHM.
        If only one value is given it is used for both axes. Default=1,1

Key: nants
        Number of antennas in array. Single antenna is OK too. Default=9.

Key: bw
        Bandwidth in MHz used for continuum observations. Default=800 MHz.

Key: deltav
        Velocity resolution in km/s  can be used to compute bandwidth for
        spectral line observations. Default=0 km/s, i.e. use bandwidth value.

Key: inttime
        Total Integration time on source in minutes. Default=1 minute.

Key: coreta
        Correlator efficiency factor. A perfect correlator has coreta=1.
        2-, 3-, and 4-level correlators have coreta=0.64, 0.81, and 0.88
        respectively. (see Thompson, Moran, and Swenson, p229).
        Default=0.88

Key: rmsphase
        RMS phase noise (degrees). Phase noise reduces the signal, effectively
        increasing the observed RMS noise in the data by a factor
           exp(rmsphase(radians)**2/2.). For strong sources atmospheric
        phase noise can be removed by selfcalibration.
        Default=0. degrees. i.e. perfect data.