ALMA Phase Correction Workshop

Allegro, Leiden, May 30 – June 3, 2016

A workshop focused on how to improve the ALMA phase corrections is jointly organized by the ALMA observatory and Allegro. It will be held at Leiden Observatory from May 30 – Jun 3. Participation is by invitation only. Find more details below:


 

DESCRIPTION

ALMA imaging observations – particularly on long baselines – are often limited more by phase fluctuations than atmospheric transmission or PWV. To enable more long-baseline or high-frequency observations, or improve existing data, we need to look at ways to improve the phase correction.

The aims of this workshop are:

  1. Review the methods that could improve ALMA phase correction and image fidelity. Including (but not limited to) baseline accuracy, WVR corrections, pressure and other environmental fluctuations, cycle times, online/offline WVR correction.
  2. Summarise the results from the related test observations during the 2014 and 2015 long-baseline campaigns, and identify and quantify the methods that do produce noticeable improvements.
  3. Make recommendations for changes in ALMA software, hardware and/or observing methods which will improve phase correction

 

PROGRAM
A pdf detailed version of the program can be found in this link: Phasemeeting_final_agenda
 

Mon 30/05 (Afternoon Session) Room HL 204
13:30-13:45

Welcome & Logistics

Remo

13:45-14:15

Outline of the meeting & Topic Organisation

Ed – Bill

Single Source Statistics
14:30-15:00

ALMA Long Baseline Campaign 2014/2015 – Basic Phase Characteristics & Pseudo cycling

Satoki

15:00-15:20

COFFEE BREAK
15:20-15:50

ALMA Long Baseline Campaign 2014 – Weather Correlations & Use of the Two-Point-Deviation

Luke

16:00-16:30

Examination of the GonoGo criterion – Results from 2014/2015 –

Bill

16:40-18:00

Open Discussion Time

 

Tue 31/05 (Morning Session) Room HL 204
WVR Discussions
09:00-09:45

Introduction to Radiometer-based Phase Correction – Principles, Instrumentation and Application

Richard

10:00-10:20

The O2 Oxygen sounder – Applicability in better atmosphere models

George

10:20-10:30

COFFEE BREAK
10:30-10:50

WVR application timescale, 1 sec vs. 6 sec

Ed

11:00-11:30

Optimising WVR solutions (scaling) – improved phases and images

Luke

11:40-12:00

Cloud Continuum removal – Effectiveness, applicability

Bill

12:10-12:30

TelCal WVR online, monitoring and phase RMS calculations

Dominique

12:40-13:00

Correlation of changes with measured pressure over the array

Satoki
Tue 31/05 (Afternoon Session) Room HL 204
14:00-15:00

Open Discussion Time
15:00-15:20

COFFEE BREAK
Antenna Position Measurements
15:20-15:40

‘Inside’ Tc Antpos – phase correction, analysis, SPW combination and plots

Dominique

15:50-16:20

Long baseline antenna measurements

Todd

16:20-16:40

COFFEE BREAK
16:40-17:10

Are antenna position changes related to tropospheric changes?

Ed

17:20-17:40

Suggested observing strategies for the next long baselines to reduce the effect of ‘changes’

Ed

17:40-18:30

Open Discussion Time

 

Wed 01/06 (Morning Session) Room HL 106
Phase referencing statistics
09:00-09:20

Is the GonoGo criteria good for estimating the phase referencing scheme

Bill

09:30-10:00

Phase referencing statistics and correlations – Fast switching experiments 2014/2015. Details of source separation, cycle time and image quality. When does and doesn’t fast switching work

Yoshi

10:10-10:20

What about the calibrators? Searches and contributions

Anita

10:30-10:40

Multi frequency AGN survey with the KVN

Taehyun

10:40-10:50

COFFEE BREAK
10:50-11:10

Pushing bands 9 and 10 beyond 5 km configurations – ‘normal’
observing techniques

Ed

11:20-11:40

Testing phase referencing in marginal conditions – does very-fast
referencing really help

Yoshi – Ed

11:50-12:10

Diurnal properties of the long baseline phase statistics

Bill – Ed

12:00-13:00

Open Discussion Time
Wed 01/06 (Afternoon Session) Room HL 106
Astrometry
14:00-14:20

Astrometry results from the long baseline campaign – multi source observations for accurate astrometry

Antonio

14:30-15:00

Is this single test sufficient, further examination, astrometry runs, multi calibrators in science data

Ed – Antonio – Open discussion

15:00-15:20

Long term astrometry: Parallax studies, proper motions, planet/stellar wobbles – tests, feasibility, offered observation modes for LB?

Ed

15:20-15:30

COFFEE BREAK
15:30-15:50

Check sources for Astrometry

Ed

16:00-17:00

Open Discussion Time
Group Meal Evening — Belgisch Bier Cafe Olivier – 7 pm (Directions)

 

Thu 02/06 (Morning Session) Room HL 106
ALMA Long Baseline experience
10:00-10:20

Lessons Learned at LB (1)

Crystal (LINK)

10:30-10:50

Lessons Learned at LB (2)

Anita

11:00-10:20

The use of Check sources during the observations – What the QA2 current script does with check sources and plans for improvements

Todd (LINK)

11:20-11:40

COFFEE BREAK
11:40-12:40

Open Discussion Time
Thu 02/06 (Afternoon Session) Room HL 106
Higher Frequencies
14:00-14:20

ALMA Band-to-Band (B2B) tests attempts

Ed

14:30-14:50

Band 3 to Band 7 fast switching results

Yoshi

15:00-15:20

Dual frequency simulation using sub-arrays – Band 3 to 6 tests

Luke

15:20-15:40

COFFEE BREAK
15:40-16:00

ALMA High Frequency calibrator cone searches

Yanett – Carmen

16:10-17:30

Open Discussion Time

 

Fri 03/06 (Morning Session) Room HL 106
Summary and Future
09:30-10:00

Conference Summary

Remo

10:15-…

Open Session

 

PRESENTATIONS

Please, find the workshop presentations and summary in the password protected area (password notified by email, no username required):
Link to online presentations and presentations review.

 

LOGISTICS

The workshop is jointly organized by the ALMA observatory and Allegro, the Netherlands ARC node. It will be held at Leiden Observatory from May 30 – Jun 3. Participation is by invitation only.

-Accomodation
Hotel occupancy in Leiden is expected to be high for this period and you are urged to book early. A block reservation has been arranged at the IBIS hotel, opposite Leiden Centraal railway station: Link to Ibis hotel

This booking is held until 18/04/2016. After this date rooms that have not been reserved will be canceled. Workshop attendees receive a discounted price. Reservations need to be made via email to H8087-RE@accor.com mentioning the booking code STER280516:
o Single room incl. breakfast: €81.50 (€ 79 room plus € 2.50 tax per person/per day)
o Double room incl. breakfast: €97.00 (€92 room plus €2.50 tax per person/per day)

-Transportation
For those of you staying at the IBIS hotel situated adjacent from Leiden Centraal Station there will be taxis arranged to take you to the university and back each day. There will be enough space for ~15 people in total.

Leave Ibis Leave University
Monday

13:00

18:00
Tuesday

08:30

18:30
Wednesday

08:30

17:30
Thursday

09:30

17:30
Friday

09:00

12:30

As an alternative there are regular buses from the station, buses 43 (direction Den Haag) or bus 57 (direction Nieuw Vennep). These take around 7 minutes. Please see the link below for more specific details if you will be coming by bus.

Instructions on how to get to Leiden Observatory, including transportation from Schiphol Airport, can be found here:
http://www.lorentzcenter.nl/howto.php
And a site map can be found here:
http://www.lorentzcenter.nl/map_LC_hotels_stat_web.php

Note these specify the route to the Lorentz Center, which is in the forward leaning building in the photo. Leiden Observatory and Allegro are located on the 4th and 5th floor of that same building. Note that this is not the old Observatory in the center of Leiden. The workshop will be held on the First and Second floors of the joining building – The Huygens Building (HL) – in either rooms 204 or 106 (see directions below).

-Directions inside the building:

Room 106:
room_106

Room 204:
room_204

Allegro offices:
allegro_offices

-Remote participation:

WEBEX link for remote participation (only Mac and Windows OS):

https://meetings.webex.com/collabs/#/meetings/detail?uuid=M6YLWHU19C3ENKOPN2PJFMIJCE-EIHZ&rnd=692476.57822

This is be open every day of the meeting, you simply click and follow the instructions below (see also Webex_Getting_Started ).

Instructions:
– Use a Windows or Mac OsX computer (NOT Linux) and point the browser to the provided link.
Firefox works, but there are sporadic reports of Safari not working. To be safe, also quit
Skype before you start since under some conditions it can latch on the mic/speaker.

– After signing in (your name and an email address) click the large button on the left “Connect to Audio” –> “Call Using this Computer –>
(select correct audio devices –> be sure to hit “OK” (audio won’t work in meeting until you hit the “OK”). (See page 1 & 3 of the attached guide).

– If possible, use earphones with a microphone.

– Note there are tabs (upper left) for different pages, so check those first if you can not find your way.

– On the right there are buttons to open “Participants”, “Chat” etc. panels. If you make your window large enough it
is possible to have both panels open at the same time. Chat will work even when audio/video is not working
(assuming the person on the other end keeps an eye on it).

– The gear box above the video panel allows you to set the video source (it default for a mac to the camera
on the notebook display which may be closed and you’ll have to then set it to the camera on the external display.)

– The “audio” button below the participants list opens the audio selection/test panel.

-Conference dinner:
The evening meal will be on Wed 7 pm at the Belgisch Bier Cafe Olivier – Hooigracht 23, 2312 KM Leiden.
Find directions from Leiden Centraal station to the restaurant here:
MapToOliviers

And the menu here: Menu_Olivier_Eng

 

PARTICIPANTS

Name
Anita Richards
Richard Hills
Satoki Matsushita
Yoshiharu Asaki
Bill Dent
Ed Fomalont
Ray Blundell
Juan R. Pardo
George Bendo
Scott Paine
Dominique Broguiere
Taehyun Jung
Neil Phillips
Michael Bremer
Bojan Nikolic
Antonio Hales
Allegro

 

Requested remote participation (see instructions here):

Name
Crystal Bogan
Todd Hunter
Liz Humphreys
Alan Roy