[mmaimcal] Re: MMA configurations

[Min Yun]

Simon,

I had this discussion on practical considerations of the array
reconfiguration schemes before with Peter and Al when I was
working on that cost-benefit analysis memo.  For example,
attached is just part of the exchange between Al and I had 
previously, and much of the same concerns were expressed as well.  

I want to add just a couple
of twists to the issues you touched on your previous e-mail.
First of all, being more pessimistic about the move time may
be much closer to reality because we most likely will not have
drives between the pads that are leveled and straight.  For the
SMA configurations at Mauna Kea, a factor 2 increase in the
drive distance seemed reasonable given their curvy road layout.
In many cases, we may have to drive around various obstacles
at Chajnantor as well, particularly for the long configurations.  
Also, we should try not to cut corners on manpower during the
reconfiguration since the safety should be the utmost concern.
At such an altitude, especially.  Both at OVRO and Hat Creek, some
4-6 people walk along each telescope during the move,
and the cabling is figured out well in advance.  Certainly at
OVRO, reconfiguration is called off if they is any chance of
bad weather.  Safety, safety, safety.  I think our French 
counterparts will agree completely.  As much as I would like to
push the scientific aspects, I have hard time arguing against
these safety cautions.




					-- Min


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