Visibility Data Calibration
Daniele Dallacasa
- The Correlator [Black Box] output:
- Interferometric measure
- time, interf., baseline [u,v,(w)], amplitude
- (RR,LL,RL,LR) phase, weight, flag ....
- Bandwidth [IF(s) and CHANNEL(s) when relevant]
- Time integration
- Smearing / need of band pass calibration?
- time, interf., baseline [u,v,(w)], amplitude
- Quality checks on the data: editing of bad points (easy for calibrators!)
- (sometimes invalid) Assumptions:
- Calibrators are pointlike, at the field center
- Instrumental and atmospheric parameters vary smoothly with time
- Raw data and primary calibrators
- The role of secondary calibrations
- phase reference
- checks on raw visibilities
- (?need of a calibration source for the instrumental polarisation)
Outcome --> good scheduling means easy calibration!
- (AIPS) Practical calibration: relevant tasks SETJY, CALIB, GETJY,CLCAL
- Important checks on (total intensity) calibration (e.g. SNPLT)
- What to do when something is wrong
- Error reckognition in the images
Optional(I guess this will be covered by Tim)
- Instrumental polarisation (parallactic angle, AN table, PCAL)
- Absolute orientation of the (Electric) polarisation vector (LISTR, CLCOR)
- When polarisation observations are critical
