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If a polarisation calibrator is included to calibrate the H-V phase of the system the observer should
consider an optimal LST time for the calibrator visit to ensure that power is available on the crosshand visibilities for their choice of parallactic angle (i.e. the parallactic angle rotated Stokes U component should be maximized). The measured fractional polarisation power for each feed should be at least 0.45 Jy (~5.3% on 3C 138 and 3% for 3C 286).At present the OPT system will not warn the observer if this is not the case, but this functionality is being worked on. An ipython notebook is available to calculate the HV power for a given scan start time. Please contact the helpdesk should you require assistance

The Observing Planning Tool (OPT) calculates and plots source H-V power values (in Jy) as part of the OPT simulate functionality, along with a correlator mode specific H-V limit (in Jy). Users can ensure that sufficient H-V power is obtained by confirming that the chosen calibrator (3C 138 or 3C 286) has a H-V power above the provided limit across the LST range it is observed for.

Cross-hand delays and V/H phase difference

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