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Concatenation

Before you attempt to use DBCON, I suggest that it would be useful to read the DBCON EXPLAIN file. DBCON will concatenate two single-source files. To combine more than two requires you to run DBCON a number of times, always appending the new file to the output of the previous concatenation.

DBCON can make some checks to make sure that you are not combining data that it thinks do not merit concatenation. It can check consistency of frequency and position. At this point, however, I am only considering the combination of data for the same source at the same frequency from different configurations and observing dates. Discussion of how to combine data of different frequency is delayed until the discussion of imaging (§ 15).

DBCON
inname,inclass First input file
inseq,indisk to combine
in2name,in2class Second input file
in2seq,in2disk to combine
reweight=#,# May need to set, otherwise leave 0
dopos(1,1)=1 Check phase centres
dopos(2,1)=1 Check for frequency agreement
doarray=-1 Separate input files in time by 5 days

The end result of all this should be one single-source file (for each source and frequency) containing data from two or more observing runs.

If you are combining multi-channel data bases (e.g., for spectral-line work), you can only combine data bases with identical frequency axes. This means they should have the same number of channels and the header items describing the axis should be the same. This is why CVEL\ does not change the frequency axis description.


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Next: A warning for users Up: HOW TO COMBINE MULTI-CONFIGURATION Previous: HOW TO COMBINE MULTI-CONFIGURATION

nkilleen@atnf.csiro.au