BIWEEKLY CALENDAR OF THE ALMA PROJECT at NRAO October 11, 2004 -- October 25, 2004 ******************************** THIS FORTNIGHT********************************* The ALMA Management Advisory Committee meets 11 - 12 October in Florence, Italy with the ALMA Management IPT and the JAO. --------------------------------------------------------------------------- The ALMA Science Software Requirements Committee meets 11 - 12 October in Garching, Germany. --------------------------------------------------------------------------- Simon Radford announced that he will depart NRAO 2004 November 1 to assume a post at Caltech as Asst. Project Manager for the Caltech/Cornell 25m telescope to be constructed at Chajnantor. Simon pioneered the characterization of the Chajnantor site, now home to several observatories--CBI, ASTE, APEX and a new survey telescope from Nagoya Observatory. As Site IPT lead for NA he has managed the planning for the construction of the AOS on the site. --------------------------------------------------------------------------- Domenick Tenerelli has resigned from AMAC and will not be at the Florence meeting of the AMAC being held 11-12 October. He has served on the AMAC and its predecessor, the MOC, since their inception. --------------------------------------------------------------------------- Janet Bauer has resigned from NRAO on 1 October. ---------------------------------------------------------------------------. John Webber has agreed to become the new ALMA Front End IPT Leader, replacing Charles Cunningham and reporting to the NA ALMA Project Manager. Charles will remain in the FE IPT as senior technical expert contributing to high level design work. John will also retain his position as ALMA Correlator IPT Leader. ---------------------------------------------------------------------------. Past issues of this Calendar may be viewed at http://www.cv.nrao.edu/~awootten/mmaimcal/ALMACalendars.html ******************************************************************************* General Happenings Please see the October NRAO Newsletter for a report. DAILY CALENDAR (Times EDT ) Mon 11 October All day events: NRAO Holiday AMAC Meeting, Florence, Italy SSR FAce-to-face Meeting, Garching, Germany Tue 12 All day events: AMAC Meeting, Florence, Italy SSR FAce-to-face Meeting, Garching, Germany Wed 13 Thu 14 11:00 AM Calibration Group telecon Fri 15 October 10:30 AM-11:30 AM: CCB Meeting Sat 16 Sun 17 Mon 18 9:30 AM-10:30 AM: NA Project Office Staff Meeting Tue 19 10:30 AM-11:00 AM: Science IPT Telecon Wed 20 Thu 21 8:30 AM-10:00 AM: JAO Teleconference Fri 22 Sat 23 Sun 24 ****************************** UPCOMING EVENTS ****************************** ALMA Calendar * 11-12 Oct -- AMAC Meeting, Florence, Italy * 11-12 Oct -- Science Software Requirements group meeting, Garching * 11-13 Oct -- New Windows on Star Formation in the Cosmos University of Maryland, College Park, Maryland * 18-19 Oct -- PDR for the Tunable Filter Bank card; Bordeaux * 19 Oct -- ASAC Telecon * 27-29 Oct -- Dusty and Molecular Universe Paris * 29 Oct -- ANASAC Telecon * 1 Nov -- ALMA JAO and Executives Face-to-face Meeting, Santiago * 2-3 Nov -- ALMA Board Face-to-face Meeting, OSF, near San Pedro de Atacama * 2 December -- ALMA Board Telecon * 5-7 Jan 2005 -- UNSC URSI Boulder meeting Commission J * 6 Jan 2005 -- ANASAC Telecon * 11 Jan 2005 - ALMA Town Meeting, AAS San Diego * 27 Jan 2005 -- ALMA Board Telecon ******************************* TECHNICAL NEWS ******************************* ALMA Memo # 505 Bandpass Calibration for ALMA A. Bacmann (ESO), S. Guilloteau (IRAM/ESO) This memo contains a detailed evaluation of the expected performance of the bandpass calibration for ALMA. We evaluate the limitations on the bandpass accuracy due to the imperfect knowledge of the atmospheric transmission. We show that the best bandpass accuracy is obtained when the amplitude calibration is applied in a single-load scheme. The proposed scheme is a variant of the so-called bandpass normalization technique. It uses normalization by the difference between the sky emission and the load emission, rather than normalization by the auto-correlation spectrum in the usual case. Bandpass calibration should be performed at the observing frequency. It will be limited by the knowledge of the sideband opacity difference. This knowledge can be based on a model, but a direct measurement is also possible, although time consuming. The bandpass calibration must be performed on strong point-like sources, of known spectral index. The knowledge of the spectral indexes will be a limiting factor in the wide band modes. Building up a database of suitable sources will be necessary, since the knowledge of these spectral indexes could be improved by bootstrapping techniques among several sources. Since astronomical sources have to be used, the required integration time varies substantially as a function of frequency. High accuracies can be reached in a minute of time at mm wavelengths, but integration time as large as an hour can be needed at sub-mm wavelengths. Occasional direct measurements of the sideband opacity difference could also be used to improve the accuracy of the atmospheric modelling. View a pdf version of ALMA Memo #505 at http://www.alma.nrao.edu/memos/html-memos/alma505/memo505.pdf ---------------------------------------------------------------------------. ALMA Memo # 483 The ALMA 1st Local Oscillator Reference Bill Shillue, Sarmad AlBanna, and Larry D'Addario National Radio Astronomy Observatory The ALMA 1st LO Reference system consists of a laser synthesizer, active line length correction, photonic distribution, and a photonic receiver. The phase stability and phase drift specifications are very ambitious, and the effort to meet them has led to small evolutions and improvements in the design. This memo gives a general description of the system, and documents its current measured performance levels, as measured in the laboratory. View a pdf version of ALMA Memo #483 at http://www.alma.nrao.edu/memos/html-memos/alma483/memo483.pdf *******************************ALSO OF INTEREST******************************* ******************************************************************************* Please send information for upcoming calendars by Friday evening of the preceding biweekly period to Jennifer Neighbours or Al Wootten via e-mail (jneighbo@nrao.edu or awootten@nrao.edu). The calendar will be issued between late Friday and sometime on Monday by e-mail to all NRAO scientific staff members and anyone else interested. A specific mailing list, alma-info, has been created for anyone wishing to receive it. Past issues are now available at http://www.cv.nrao.edu/~awootten/mmaimcal/ALMACalendars.html