Check the fluxes of the calibration sources

Last updated: sep17

      The plots below show the gain ratio for all  calibration sources plotted versus frequency. There are 4 plots per page. Each plot holds 5 sources. Sources are distinguished by color and symbol. The large  variation for some sources (especially at higher frequencies) is caused by   collimation errors (and the gain fits inability to fit it).

How the fluxes were checked:

    The telescope gain curves are made using a set of calibration sources selected by chris salter. The fluxes of these sources are tabulated in different catalogs  at discrete frequencies. Chris has fit these  fluxes to the functional form:
let y=log10(fluxJy)
let x=log10(freqMhz)
y= a0 + a1*x + a2*exp(-x)
    To compute a gain curve for a receiver we do a number of calibration scans using some of the calibration sources and then fit the gain as a function of azimuth and zenith angle.

    To check that the source fluxes used are ok we have computed:

        gain_from_a_single_measurement/ gain_from_gaincurve_model_fit

We do this for each calibration scan taken for all receivers.
Some things to keep in mind are:

processing: x101/sysperf/chkflux/

 Systemp_performance page: