[mmaimcal] BIWEEKLY CALENDAR OF THE ALMA PROJECT at NRAO

Mon Nov 22 16:18:21 EST 2004

                        BIWEEKLY CALENDAR OF THE ALMA PROJECT at NRAO
                            November 22 -- December 6, 2004

******************************** THIS FORTNIGHT*********************************
Both Houses have passed the omnibus budget bill containing ALMA funding.
--------------------------------------------------------------------------- 

Past issues of this Calendar may be viewed at 
http://www.cv.nrao.edu/~awootten/mmaimcal/ALMACalendars.html
*******************************************************************************
General Happenings
Santiago:  The JAO address is Santiago is: Joint ALMA Office; El Golf 40 18th 
floor Las Condes  7550107 Santiago Chile.  Videocon IP:  200.7.18.100

SPdA:  A Board Change Request confirming the scope and cost of the ALMA Camp and
the ALMA Contractor's Camp was approved.  An invitation for bid for the 
completion  of the Contractor’s Camp and enlargement of the ALMA Camp will be 
released during this month.  Road construction progresses between km 26 
and km 28. The BBC visited the site on 19-Nov-2004.

Tucson: Testing of prototype modules for Prototype System Integration continues.
Phase noise tests underway of LO reference signals.

AOC: 	Studies of fiber optic polarization mode dispersion (UK) and design of 
antenna cable wraps (Socorro).  Allan variance tests on Vega 1 digitizer show 
satisfactory performance for testing and even 1st science.  DTS link stability 
tests underway by backend group.  reliability analysis interim report for
computing subsustem completed and distributed for review.

NTC:  Two more correlator racks have been completed and are ready to be populated.  
93% of the cards needed for the first quadrant have been received and checked out.
For the second quadrant, we have 26% received and checked out.
All 1321 signal cables for the first quadrant were received and preliminary tests 
show no problems.  A New engineer from Chile, Alejandro Saez, expected to start 
late January 2005
Tests of Band 6 (1.3mm) cartridge beam sidelobe and prototype bias continue.

NAASC:  An ALMA Update and report on the ALMA/Herschel meeting 'Dusty04' will be
given at Tuesday lunch.

DAILY CALENDAR (Times EDT )
 Mon  22
 9:30 AM-10:30 AM: NA Project Office Staff Meeting
10:30 AM-11:30 PM: JAO/IPT Teleconference
11:30 AM-12:00 PM: NA Div Heads Teleconference
                   Management meeting at NSF.
 Tue 23
NAScienceIPT teleconference (open to all interested 
                                 parties) (434)296-7082
             Agenda: http://www.cv.nrao.edu/~awootten/mmaimcal/ 
 Wed  24  
 Thu  25
All day event: NRAO Holiday -- Happy Thanksgiving!
8:30 AM-10:00 AM: JAO Teleconference
 Fri  26
All day event: NRAO Holiday
 Sat  27
 Sun  28 
 Mon  29
10:30 AM-11:30 PM: JAO/IPT Teleconference
11:30 AM-12:00 PM: NA Div Heads Teleconference
 Tue  30
NAScienceIPT teleconference (open to all interested 
                                 parties) (434)296-7082
             Agenda: http://www.cv.nrao.edu/~awootten/mmaimcal/ 
 Wed  01 
 Thu 02
 8:30 AM-10:00 AM: JAO Teleconference
 12:00 PM-01:30 PM: ALMA Board Teleconference
 Fri 03  
 Sat 04  
 Sun 05 

****************************** UPCOMING EVENTS ******************************
ALMA Calendar  

    * 2 December -- ALMA Board Telecon
    * 14 December -- ASAC 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 *******************************
One prototype, after retrofitting, will proceed to Chajnantor.  A report on it:
Design and performance of the ALMA-J prototype antenna
Nobuharu Ukita, Masao Saito, Hajime Ezawa, Bungo Ikenoue, Hideharu Ishizaki, 
Hiroyuki Iwashita, Nobuyuki Yamaguchi, Takahiro Hayakawa, and the ATF-J team

The National Astronomical Observatory of Japan has constructed a prototype 12-m 
antenna of the Atacama Compact Array to evaluate its performance at the ALMA 
Test Facility in the NRAO VLA observatory in New Mexico, the United States. The 
antenna has a CFRP tube backup structure (BUS) with CFRP boards to support 205 
machined Aluminum surface panels. Their accuracies were measured to be 5.9 µm rms 
on average. A chemical treatment technique of the surface panels has successfully  
applied to scatter the solar radiation, which resulted in a subreflector temperature
increase of about 25 degrees relative to ambient temperature during direct solar  
observations. Holography measurements and panel adjustments led to a final surface  
accuracy of 20 µm rms, (weighted by 12dB edge taper), after three rounds of
the panel adjustments. Based on a long term temperature monitoring of the BUS and  
thermal deformation FEM calculation, the BUS thermal deformation was estimated to 
be less than 3.1 µm rms.  We have employed gear drive mechanism both for a fast  
position switching capability and for smooth drive at low velocities. Servo errors 
measured with angle encoders were found to be less than 0.1 arcseconds rms at rotational
velocities below 0.1 degrees s-1 and to increase to 0.7 arcseconds rms at the 
maximum speed of the ‘on-the-fly’ scan as a single dish, 0.5 deg s-1 induced by 
the irregularity of individual gear tooth profiles. Simultaneous measurements of 
the antenna motion with the angle encoders and seismic accelerometers mounted at 
the primary reflector mirror edges and at the subreflector showed the same amplitude 
and phase of oscillation, indicating that they are rigid, suggesting that it is
possible to estimate where the antenna is actually pointing from the encoder readout. 
Continuous tracking measurements of Polaris during day and night have revealed 
a large pointing drift due to thermal distortion of the yoke structure. We have 
applied retrospective thermal corrections to tracking data for two hours, with a 
preliminary thermal deformation model of the yoke, and have found the tracking 
accuracy improved to be 0.1-0.3 arcseconds rms for a 15-munites period. The 
whole sky absolute pointing error under no wind and during night was measured 
to be 1.17 arcseconds rms.  We need to make both an elaborated modeling of thermal 
deformation of the structure and systematic searches for significant correlation 
among pointing errors and metrology sensor outputs to achieve the stable tracking 
performance requested by ALMA.

View a pdf version of Proc. SPIE 5489, pp. 1085-1093:
http://www.cv.nrao.edu/~awootten/mmaimcal/SPIE_5489-73c.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 at nrao.edu or awootten at 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