October Science Meeting
The meeting began with a short summary of where the plans stand for the Science Meeting in October. Al reminded us that the deadline for reduced registration fees had passed but that it will be extended for another week through September 3, 1999. The Congressional Reception on October 6th (5:30-7:30 p.m.) will be by invitation only due to space limitations. Those of you who will be hosting a member of congress or members of their staff should let Rebecca Johnson at NRAO know ASAP so invitations can be issued as early as possible. Chris Chyba cannot give a talk so suggestions for an alternative speaker would be welcome. Contact Al about this. Joe Taylor and Bill Wilson are not yet confirmed so there is a possibility that alternative speakers for one or both of them may be needed.

The press conference has been moved from 8:00 a.m. to 10:30 a.m. to accomodate the late sleepers. The conference proceedings will be published by PASP at a cost of $52/book. Registrants will have a chance to order the book at registration. Al will send out ALMA specs and sensitivities for each speaker to use so we all use the same numbers. These are available at: http://www.alma.nrao.edu/info/ under the eighth bulleted item.

Canadian Participation
Canadian astronomers are almost finished with their equivalent of decadal review process. Chris Wilson informed us that ALMA is their highest priority ground-based project and Canada would like to join the project. Chris Wilson will be the Canadian project scientist. As a consequence, Chris has joined the MAC as a mechanism to keep informed on developments with the project and as a representative of the Canadian astronomy community. We welcome her to the MAC and Canadian participation in the project.

They do not have funding for participation in ALMA yet, but expect to submit a request in the next budget cycle (February 2000). They would like to join at about 5-10% of the currently defined US-European project. In the meantime, they are actively building a 183 GHz radiometer which they expect to apply to the water vapor testing effort for ALMA. They also hope to provide a 230 GHz receiver to help with testing of the prototype antennae.

Water Vapor Monitors
At a recent meeting of the division heads, it was decided to use the 183 GHz water line to monitor the atmospheric water vapor column. A recent memo (No. 271) reports on recent measurements on Chajnantor. It is expected that such measurements will help to define and refine a WVR system. The 183 GHz recievers are expected to be placed in the dewar with the other receivers. Real estate at the focal plane is not expected to be an issue.

URSI Meeting
The US and European division heads met on Tuesday, October 17 to discuss details of how to join the US and European projects. The issues discussed were not publicized.

Configurations
Work continues on configuration geometries but no generally agreed upon plan has yet emerged. Several types of geometry have been considered and clearly further time on this important issue will need to be invested. Unfortunately for the ALMA, Tamara Helfer has resigned to work with Rob Kennicutt. We wish her well but will miss her work on the ALMA configuration studies.

Al noted that AIPS, GILDAS, and MIRIAD (and AIPS++ sometime soon) are being used in this effort. It was noted that about 80% of the flux from an M51-like image was recovered in a compact array simulation. It is hoped to improve on this.

Continuous movement of antennae as opposed to episodic changes of configuration are being considered. Continuous antenna position changes seem to have several advantages, however, there are questions regarding the time required to obtain baseline solutions and accomodations of long term projects that require a specific configuration from one epoch to the next.

7mm Receivers
The European scientists were not convinced of the necessity of including a 7mm receiver (31.3-43 GHz, range set by LO design) in the suite of ALMA receivers. John Carlstrom pointed out that a 7mm receiver on ALMA would provide greater sensitivity at this wavelength than the upgraded VLA and shorter baselines than the VLA at a small fraction of the project budget. It was also pointed out that the pressure on the VLA at 7mm is high. Clearly, the scientific benefits of a 7mm capability versus costs, focal plane real estate, capability of other telescopes, etc. needs to be discussed further.

Prototype Antennae
Peter Napier told us that 4 bids were received at the end of June for the US prototype antenna contract. The Europeans received 6 bids. NRAO will be negotiating further with two of the companies this week. It is expected that in the 3rd or 4th week in Sept. the US and Europeans will meet to discuss the bids

The prototype antennae will have the capability to nutate. Planned capability now is by 3 beamwidths at 5 Hz. This will permit testing of total power mapping modes with nutation versus rapid telescope position switching. The present plans are for delivery of the first prototype antenna to the VLA site in the 3rd quarter of 2001. The prototype interferometer is expected to be available in the 2nd quarter of 2002. The current schedule is to sign the contract for the production antennas in January 2003 which calls for the first of those production antennas to be delivered to the Chile site March 2004. What is to be done with the test interferometer between Januar 2003 and March 2004? It will stay at the VLA site for receiver tests, electronics system debugging, etc. In 2004 the test interferometer will be disassembled and shipped to Chile where it will become part of the ALMA array.

We were told that the Japanese are moving rapidly forward with a 10m prototype. They expect to have it delivered to NRO in December of this year and they hope to move it to their Chilean site in the 1st quarter of 2001.

LO Designs
Larry D'Addario has essentially completed an LO design in which the 1st LO will be stepped by 2 GHz. There is a question of whether the LO can be tuned in small enough steps for some programs. The issue of a photonic versus a traditional LO is still not decided.

Large Single Dish
The question of a large single dish as an element in the array was raised again along with the possibility of including the smaller 10m Japanese dishes in the array. More issues that may need further discussion.

The Project Book
Darrel Emerson is in the process of including the specifications for ALMA into a single chapter of the Project Book so one can find all the relevant numbers in one place. A great idea.

THE NEXT MAC TELECON WILL BE SEPT. 15TH AT 12 NOON EDT. THE NUMBER IS 804-296-7082.