[evla-sw-discuss] Reference pointing

[Barry Clark]

I didn't particularly follow your example, Bryan.  

There are two things that can reasonably be called 'double reference 
pointing'.  The first is to use a lower frequency pointing scan to be 
sure you are within the range of good solutions for a pointing scan at 
the high frequency.  That is the case my example handled.  Something 
that made my explanation less clear than it might have been is that the 
refPointingAgent would know what reference pointing was used at the time 
of the pointing scan, so that the registered refPointings receive the 
total offsets, not just the change above single reference pointing.

If you were instead talking about the other sort of 'double reference pointing',
of on-the-fly determination of relative collimation errors between two 
frequencies, so that you could do all your reference pointing for a Q 
band observation at X band, I hadn't addressed that issue.  Do we want
to get into that issue now?  (If so, I think I'd do it as an add-on routine 
to add or subtract two sets of RefPoingtings, to be used at script level.)