[mmaimcal] BIWEEKLY CALENDAR OF THE ALMA PROJECT at NRAO
Al Wootten
awootten at nrao.edu
Wed Feb 16 18:19:39 EST 2005
Folks,
Please note back to me errors, omissions, bloopers or fibs.
Al
BIWEEKLY CALENDAR OF THE ALMA PROJECT at NRAO
February 14 -- February 28, 2005
******************************** THIS FORTNIGHT*********************************
Adrian Russell arrives in Charlottesville 20 February. Welcome, Adrian!
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Marc Rafal will serve as Interim North American Antenna IPT lead.
Victor Gasho, who has held this post, left the Observatory effective
11 February 2005 to join the Steward Observatory, as previously reported.
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The ALMA Project Scientist job has now been advertised on the NRAO website.
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The ALMA Scientific Advisory Committee will meet in Garching 24-25 February.
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Tony Kerr, a pioneer of the use of SIS junctions in receivers from the 12m
to ALMA and beyond, is a recipient of one of the Observatory's Distinguished
Performance Awards for 2004.
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Springer Verlag has just published a history of Tucson Operations. Entitled
" 'Recollections of Tucson Operations', The Millimeter-Wave Observatory of
the National Radio Astronomy Observatory," it was written by Mark Gordon,
one of the ALMA pioneers.
----------------------------------------------------------------------
Lee Shapiro will be resigning his position as Head of Education and Public
Outreach (EPO) at the NRAO effective March 1, 2005. We wish you well, Lee!
----------------------------------------------------------------------
Past issues of this Calendar may be viewed at
http://www.cv.nrao.edu/~awootten/mmaimcal/ALMACalendars.html
*******************************************************************************
General Happenings
Santiago: Kevin Long has begun work in Santiago.
OSF: Completion of 22 bed facility at the Contractors Camp and
emergency road repair continue. 25 people are currently working at this
site.
Tucson: ATF support during antenna tests. Redesign of LO line length corrector
80% complete. Verification tests continue on prototype
modules for the prototype system integration. Tests are underway to study
phase drift with temperature.
ATF: Holography completed on readjusted surfaces; out of focus beam
maps with Vertex antenna are under analysis.
AOC: ATF support during antenna tests. C. Janes at Fiber Management CDR in
Garching last week.
NAASC: Discussions on ALMA calibrators and other topics were held; see
wiki page for minutes.
NTC: Alejandro Saez has assumed the role of correlator engineer and
is testing correlator cards while learning the system. DTS Simulator
cards have arrived.
Work is ongoing on the evaluation receivers to allow phase locking
using the photonic LO reference for ATF interferometry.
Integrated Front End testing has commenced with the Band 6 cartridge.
Prototype cold multipliers for Band 9 were delivered to ESO which produce
adequater power over most of the band.
WVR PDR will be 4 May in Onsala.
Central Variable Reference design review March 29 in CV.
*******************************************************************************
DAILY CALENDAR (Times EST )
Mon 14
9:30 AM-10:30 AM: NA Project Office Staff Meeting
10:30 AM-11:30 AM: JAO IPT Telecon
Tue 15
10:30 AM-11:00 AM: Science IPT Telecon
Wed 16
Thu 17
9:30 AM-11:00 AM: Management IPT Teleconference
Fri 18
2:00 PM-3:00 PM: NA ALMA Telecaucus
2:00 PM-3:00 PM: ANASAC Teleconference
Sat 19
Sun 20
Mon 21
NRAO Holiday: President's Day, celebrating the birthdays of President
Abraham Lincoln (12 Feb) and George Washington (22 Feb)
Tue 22
No Science IPT telecon; some folks are on planes to the ASAC meeting.
Wed 23
Thu 24
All Day: ASAC face-to-face meeting, Garching
9:30 AM-11:00 AM: Management IPT Teleconference
11:00 AM: ALMA Board Telecon
Fri 25
All Day: ASAC face-to-face meeting, Garching
Sat 26
Sun 27
****************************** UPCOMING EVENTS ******************************
ALMA Calendar
* 24-25 Feb 2005 -- ASAC face-to-face meeting, Garching
* 24 Feb 2005 -- ALMA Board Telecon.
* 20 Mar 2005 -- Philadelphia ICASSP/IEEE meeting, Philadelphia
* 22-24 March 2005 -- JAO/IPT Meeting, Garching
* 29 March 2005 -- CVR review, Charlottesville
* 4 April -- Executive meeting, Pasadena
* 5-6 April 2005 -- AMAC Face-to-face meeting, Pasadena, CA.
* 7-8 April 2005 -- ALMA Board Face-to-face meeting, Pasadena, CA.
* 4 May 2005 -- WVR PDR, Gothenburg, Sweden
******************************* TECHNICAL NEWS *******************************
ALMA Memo # 507 ALMA First LO Reference : Elimination of Large Phase
Fluctuations due to lightwave polarization effects
Authors: Bill Shillue, S. AlBanna
Abstract: The ALMA 1st LO reference is sent from the central Array
Operations Site Technical Building to each of 64 antennas over optical
fiber. Two high-coherence and phase-locked lightwaves are transmitted that
are separated by a variable frequency ranging from 27-142 GHz. The
round-trip stabilized fiber optic distribution system has been previously
described in this memo series [1-3,13]. In August of 2003, a first
generation version of the line length correction system was tested on a
prototype ALMA antenna. These were the first systematic measurements of
the system on the moving structure. During these measurements we noticed
an undesirable and unexpected phase fluctuation which was correlated with
the antenna azimuth and elevation position. Those tests are described in
an internal test report [4]. Further tests and meetings took place in an
effort to resolve this issue [5-8]. In addition, an ALMA memo was written
describing a theoretical treatment of the measured phase fluctuation [9],
supporting the measurement results which showed that the phase fluctuation
was due to the absolute polarization change (caused by the fiber movement)
of the two lightwaves, and that the phase fluctuation magnitude was
inversely proportional to the degree of polarization alignment of the two
lightwaves. To put it another way, if the state-of-polarizations (SOPs) of
the two lightwaves were different at the receiver end, then any movement of
the fiber would cause a phase change. The purpose of this memo is to
summarize the main points from the references listed above, and additionally
to describe more recent measurements that utilize improvements to the 1st
LO reference baseline design. This is mainly an experimental report, there
is a related theoretical study as well [14].
View a pdf version of ALMA Memo #507 at:
http://www.alma.nrao.edu/memos/html-memos/alma509/memo507.pdf
------------------------------------------------------------------------
ALMA Memo # 509 G/T at 243 GHz for the ALMA Telescope
G. A. Ediss (NRAO/CV) 2004-11-23 00:00
A (limited) student version of GRASP [1] was used to analyze the
gain/system temperature (G/T) at 243 GHz for the ALMA telescope. It shows
an optimum edge taper of between -12 dB and -14 dB at the secondary mirror,
with the telescope pointing at the zenith, for the Band 6 receiver.
View a pdf version of ALMA Memo #509 at:
http://www.alma.nrao.edu/memos/html-memos/alma509/memo509.pdf
------------------------------------------------------------------------
ALMA Memo # 512 ATMOSPHERIC TRANSPARENCY AT CHAJNANTOR: 1973-2003
Angel C. Otarola, Mark Holdaway, Lars-Ake Nyman, Simon J. E. Radford,
Brian L. Butler 2005-01-14 00:00
Abstract: Atmospheric conditions at Chajnantor have been monitored
since April 1995. Starting then, the National Radio Astronomy Observatory
(NRAO), joined by the European Southern Observatory (ESO), Onsala Space
Observatory (OSO), and the Nobeyama Radio Observatory (NRO), have operated
atmospheric and weather monitoring equipment to characterize the observing
conditions for a large radio interferometer for astronomy at millimeter
and sub-millimeter wavelengths. The data have demonstrated Chajnantor is
an exceptionally good site.
In this work, we examine the atmospheric transparency at Chajnantor before
direct measurements begun. We first show the surface water vapor pressure
at Chajnantor is a good estimator of the daily-average atmospheric
transparency by direct correlation with measurements of optical depth at
225 GHz. Next, we show the surface water vapor pressure at the Calama
airport correlates reasonably well with the surface weather conditions at
Chajnantor. These findings then allow us to examine the transparency at
Chajnantor since 1973 through the analysis of the Calama surface weather data.
Besides, we also include here a determination of the strength of the
so-called Bolivian winter (regional monsoon) based on a normalized index
calculated out of surface water vapour pressure. This index helps us to
get the annual regional humidity trend, and in turn can be useful to
compare the atmospheric observing conditions from year to year.
View a pdf version of ALMA Memo #512 at:
http://www.alma.nrao.edu/memos/html-memos/alma512/memo512.pdf
------------------------------------------------------------------------
Alma memo # 514 Saturation correction with atmospheric fluctuations A. Bacmann & S. Guilloteau 2005-01-20 00:00
*******************************ALSO OF INTEREST*******************************
SMA proposal deadline for next semester (MAY 1 - OCT 31) is MAR 17, 2005
******************************************************************************
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
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