AUI News Release
Continuing Progress on ALMA
ALMA construction, integration and testing continues, with two significant new achievements at the ALMA site in Chile. On April 30, the first astronomical fringes were obtained using two accepted ALMA antennas - one Japanese and one North American - and full ALMA production or engineering-qualification hardware. A short summary appears below.
In addition, the previous day, the second North American antenna, built by Vertex, was conditionally accepted and moved a few hundred meters to the Operations Support Facility (OSF), to make room for the assembly of the next Vertex antenna. This brings the complement of ALMA antennas at the mid-level ALMA facility in Chile to 3 conditionally accepted antennas (one Japanese and two North American), 3 more assembled Japanese antennas in test, 6 more North American antennas in various stages of assembly and test, with a ninth unpacked and a tenth on the ocean, and one European antenna in assembly with other components in shipment.
The “fringe” was created by pointing at Mars, and observing the movement of the planet through the response pattern of the interferometer. It can be seen that stability is encouragingly good even at this early stage.
The hardware used included:
- the PM03 Melco 12-m antenna,
- the DV01 Vertex 12-m antenna,
- engineering Front Ends (serial numbers #1 and #7 – data taken with Band 3),
- the full production Back End system, which includes LO Photonic Receivers and the Antenna and Data Receiver Articles,
- the 2-antenna test correlator which is a subset of the 64-antenna correlator,
- the OSF version of the laser local oscillator system, which again incorporates most of the key modules that will form the system to be installed at the AOS.
This successful short integration demonstrates full hardware connectivity and functionality. Work continues in CIPT and AIV toward verifying automatic computer control of delay and Phase: key components of the target of stable and repeatable interferometry at the OSF.
While these results represent the successful work by almost everyone in the ALMA project, participating directly in the measurement were Joe McMullin, Gene Duvall, Dick Sramek, Darrell Emerson, Peter Napier, Lewis Knee, Norman Saez and Hector Alarcon.
