[evla-sw-discuss] Reference pointing

[Bryan Butler]

the use case your example doesn't handle, that mine does (i think, 
anyway), is observing at K & Q-bands, and double reference pointing at 
both (with, say, X-band as the lower band).  i believe that the way your 
example would work, you would need to do the X-band reference pointing 
scan twice.  in mine, you just do one each at X-, K-, and Q-bands, and 
then apply either X+K or X+Q, depending on the target frequency.  this 
is, for instance, how rick and i do the double reference pointing during 
the flux density runs (well, kind of, but the concept is the same).

it just seems simpler to me to not add up the offsets into a single 
object - keep them separate and apply whichever ones you wish at the 
time you observe your targets.

i wasn't thinking of the on-the-fly collimation determination, though 
it's an interesting idea.

	-bryan


On 4/11/05 15:05, Barry Clark wrote:
> 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.)
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