ALMA Configuration Working Group

Minutes of the meeting on Wed, 23 February 2000 at 12pm EST (17:00 UT).

Past minutes and listings of relevant memos and publications are found at ALMA Configuration Working Group Page

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ALMA Project Book Update

ALMA project book chapter 15 on configurations is recently updated by Min Yun. The draft version is temporarily located here. Please examine it and send comments to Min Yun (myun@nrao.edu).

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Tucson Face-to-Face Meeting on March 20-21, 2000

Jennifer Neighbours (jneighbo@nrao.edu) is handling the administrative details of the meeting. Please let her know your detailed travel plans. She can help with local arrangements.

Date: 2000 March 20 - 21 (Monday - Tuesday)
Location: Tucson, AZ (USA)
Varsity Suites Hotel
Speedway & Alvernon, 2 miles E of campus
rooms @ $80 /night plus tax

The agenda for the meeting will eventually be found here.

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Topographic constraints and digital masks

Bryan Butler described the details of how his 5 degree slope and 10 degree slope masks are made. John Conway notes that the site is "bumpy", but he has managed to adopt his spiral zoom array to these topographic masks with some success. Optimization for the sidelobe levels (i.e. Kogan optimization) is still in the works. Check here for his current best results.

Min Yun asked Mel Wright and Dave Woody to discuss their experience with the topographic constraints for the CARMA configuration design. For CARMA, they were entirely limited by minimizing the environmental impact (thus road construction) -- pretty severely in some sense. Their experience does not seem too relevant for the ALMA case.

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Image Library and Metrics

We should consult ASAC again about the image library.

Some heated exchanges over the merit of uv versus image based metrics took place involving a number of people. We will continue in Tucson where we left off. One concrete outcome of the discussion is that the two people who have done some detailed examination of the imaging performances (Conway and Kogan) both insisted on using imaging tests as a necessary step in the configuration design evaluation. Given the limited experience thus far and the lack of concrete theoretical reasons to repute this, we will stay with this baseline plan.

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Update on Strawperson Configurations

Min Yun and Leonia Kogan are working on finalizing the details of the doubling ring design, including the togographic constraints. Some of these details are already included in the draft update of the Project Book Chapter. The strawperson zoom array by John Conway and A. Webster are similar enough that they will present a joint concept at the Tucson meeting together. Absent at the meeting was F. Viallefond, and it was not certain if he has a completely independent (and fully developed) design that needs to be presented separately. If so, this will be presented separately in Tucson.

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Next meeting will be in Tucson

Note that besides our ALMA Configuration Conceptual Design Review (CoDR) meeting on the March 20-21, 2000, there is also a site test group meeting on the morning of March 21. Contact Simon Radford if you are interested in attending.

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