C.1 Quick Guide

This section is meant as a reminder for people who have some idea how to reduce straightforward VLBI data and a familiarity with . For further details see the rest of this appendix and/or Chapter 9. This section does not include things like CVEL or AVSPEC that might be useful for spectral line observations. Also, this section refers to procedures that can loaded by typing RUN VLBAUTIL. All these steps are performed, in this order, by the 31DEC25 VLBAPIPE (section §C.5) pipeline procedure.

1.  VLBALOAD — load the data
2.  VLBAFIX — fix the data (separate frequencies, merge tables, create index table, etc.)
3.  VLBAEOPS — correct earth orientation parameters
4.  VLBATECR — (if frequency < 10 GHz) remove dispersive delay from ionosphere
5.  VLBAPANG — correct parallactic angle
6.  VLBACCOR — correct sampler threshold errors from correlator
7.  VLBAPCOR or VLBAMPCL — (if more than 1 IF) correct instrumental delays, use POSSM to inspect correction
8.  VLBAFRNG or VLBAFRGP — fringe fit data
9.  VLBABPSS — calibrate bandpass, use POSSM to inspect bandpass solutions
10.  VLBAAMP — corrects any auto-correlation departure from unity caused by previous steps and performs a-priori amplitude calibration, use SNPLT to check that nothing has gone wrong in the amplitude calibration.
11.  RFLAG — flag data that are too variable in time ot frequency
12.  SPLIT — apply all calibration and possibly average data spectrally
13.  IMAGR — image data

These steps, in a different order, are also performed by the older VLBARUN (section §C.5) pipeline procedure.

1.  VLBALOAD — load the data
2.  VLBAFIX — fix the data (separate frequencies, merge tables, create index table, etc.)
3.  VLBAEOPS — correct earth orientation parameters
4.  VLBATECR — (if frequency < 10 GHz) remove dispersive delay from ionosphere
5.  VLBACCOR — correct sampler threshold errors from correlator
6.  VLBAPCOR or VLBAMPCL — (if more than 1 IF) correct instrumental delays, use POSSM to inspect correction
7.  VLBABPSS — calibrate bandpass, use POSSM to inspect bandpass solutions
8.  VLBAAMP — corrects any auto-correlation departure from unity caused by previous steps and performs a-priori amplitude calibration, use SNPLT to check that nothing has gone wrong in the amplitude calibration.
9.  VLBAPANG — correct parallactic angle
10.  VLBAFRNG or VLBAFRGP — fringe fit data
11.  RFLAG — flag data that are too variable in time ot frequency
12.  SPLIT — apply all calibration and possibly average data spectrally
13.  IMAGR — image data