The primary constraint is that construction will begin on 1 January 2002 and the locations of the configurations, pads, and related items must be determined by that date. It appears that this date may be moved forward to 1 October 2001 by NSF. Therefore we should schedule a PDR by Fall 2000. The ASAC will meet before the ACC meets on 13 October, so that date should be set either to coincide with the ASAC meeting in Berkeley, or to precede it.
It became clear that several factors in configuration design affect cost. Designs should consider minimizing antenna pads, road lengths, conduit lengths, and fiber lengths. Transporter access is also important; tranporter design should be accomplished by late Spring 2000.
A new site mask is needed. It should include
* Roads
* Second pipeline
* EW/NS shadowing variations (north is important, +/- 15 degrees)
* The array center used by Conway
Some of these items may need remeasuring during an upcoming site visit. Bryan will finish the new mask set by May 2000.
The Compact Configurations need more work. Yun and Webster will have this done by May 2000. This includes
* Optimization (access; brightness temperature sensitivity)
* Transporter access considerations
* NS Extension of a factor of e.g. 1.1-2
* Mating to next larger array
* Mating to single antenna observations
The Large Array needs further improvement.
* What is its relation to the next smaller array?
* Can roads be minimized--how can the antennas be accessed?
* Can pad sharing be utilized?
Webster will examine the first of these questions with regard to the zoom designs.
Total power observations have many unanswered questions.
* Modeling -- the Holdaway memo needs to be finished and issued
* Nutator -- what specifications? Radford is working on this.
* OTF mapping should be defined precisely.
* How will this data be combined with the array data? Simulations would be useful.
Some observations may require multiconfigurations--Lee Mundy did some simulations of this for his protoplanetary disk models. A standard for how to accommodate these should be formulated.
Simulations will be performed, first on a standard AIPS engine with a standard library of images, then incorporating more complex erros with AIPS++. The library will be defined by the end of April, with simulations to begin during May.
We discussed having two configuration cycles per year, with the 14 km configuration once per year. Is this a good model?
How does the ultra-compact array which may be a feature brought to ALMA by the Japanese collaboration impact these designs? Morita will consider this.