This week I modified the internals of ORAC-DR to allow it to recognize hybrid observations and treat them as a single "frame" (in ORAC-DR speak). It was a little more involved than expected because there was no merging of header information in the pipeline outside of bespoke implementations in UKIRT spectroscopy and SCUBA-2 classes. I moved some header parsing code into a base class and removed the special code from UKIRT (SCUBA-2 is still special). This required some minor changes to all the header translation code but was worth it since all instruments can make use of the header merging.
Next step is to actually use this information to merge the sub-bands. One minor caveat in all this is that ORAC-DR will still not try to merge multi-subsystem observations simply because subsystems overlap. If that is required (for example for the SLS) then we need to be told the requirements.
4 comments:
Certainly there was no requirement from the SLS for a merged spectrum as part of the ADPs - although I'd imagine that either one very big or several small-but-still-big merged spectra would be something that they and other spectral survey type proposals would want.
Would it be a big hit on processing time if you had to do this over say a night's worth of data?
It's not the processing time that's the hit, it's the inability to work out whether this is required or not when processing automatically. ORAC-DR can work out hybrid modes because they have the same IFFREQ and BWMODE headers and are meant to be together. Mosaicking all data into a larger spectral extent would require a specialist PICARD recipe.
Isn't the simplest solution then to have two DR recipes that the PI chooses from in the OT - one which merges the two sub-bands and another which doesn't?
Well, hybrid modes (500 MHz and 1GHz) should always merge. That's the point. A check box in the Het Setup component indicating that merging should occur for multi-subsystem mode is a reasonable approach (there are issues when you want to merge 3 out of 4 bands for RxA or if you want to merge even if the bands don't overlap).
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