2005-10-13 ALMA Calibration Group Telecon Agenda and Minutes
ALMA Calibration Group Telecon
  • Date: October 13, 2005 (Thursday)
  • Time: 15:00 UT
  • Duration: 1.0 hr
  • USA Toll Free Number: 1-877-919-7148
  • International: +1-203-566-1039
  • Passcode: 5 1 0 4 6 8
  • Leader: JeffMangum

Table of Contents:

Complete List of Action Items

Action Items from Last Telecon

Assigned To Due Date Description State Notify  
JeffMangum 2005-09-26 Final comments on Calibration Plan due. closed JeffMangum edit
JeffMangum 2005-09-26 Final comments on Calibration Specifications and Requirements document due. closed JeffMangum edit
RobertLucas 2005-10-01 Draft of Bandpass calibration examples document due. closed RobertLucas edit
RobertLucas 2005-10-01 Draft of Delay calibration examples document due.
see document at: https://safe.nrao.edu/wiki/pub/ALMA/CalExamples/DelayCalSteps.pdf
closed RobertLucas edit
EdFomalont, MarkHoldaway 2005-11-01 Draft of ACA calibration examples document due (following Ed's visit to Mitaka). closed EdFomalont, MarkHoldaway edit

Agenda and Minutes

NOTE: Discussion from the telecon is shown in italic.


  1. EdFomalont
  2. JimGibson
  3. MarkHoldaway
  4. JeffMangum
  5. Shigehisa Takakuwa

Calibration Examples

As noted by AlWootten, an action item for Science from the Systems Requirements Review (SRR) was to fill out the "calibration examples". These "examples" should be used as "atomic" descriptions of each type of calibration, upon which we can build descriptions ("use cases", if you will) of how each type of calibration will be executed.

We now have drafts of a few of these example documents in-hand. A Calibration Examples Wiki page has been set-up for this group writing task. A final version of a document which describes the step-by-step process by which amplitude calibration is done, by RobertLucas and JeffMangum, has been posted to give an example of what I think we are looking for.

The following "volunteers" have been assigned to write these documents:

  1. Amplitude and Flux Calibration (RobertLucas, JeffMangum)
  2. Phase Calibration (MarkHoldaway)
  3. Bandpass Calibration (RobertLucas)
  4. Polarization Calibration (StevenMyers)
  5. Pointing Calibration (JeffMangum)
  6. Antenna Location Calibration (MarkHoldaway)
  7. Antenna and Electronic Delay Calibration (RobertLucas)
  8. Optics Calibration (BaltasarVilaVilaro)
  9. Total Power Calibration (MarkHoldaway)
  10. Primary Beam Calibration (MarkHoldaway)
  11. ACA Calibration Issues (EdFomalont, MarkHoldaway)

First drafts of several of the "example" documents were posted to the CalExamples wiki by September 15, 2005 (Thanks!). All should read the drafts and comment to the author with cc to the group. Those drafts which have not yet been posted should be made available to the group by our next telecon.

Amplitude Calibration Subsystem Development Reports

  • Berkeley Absolute Flux Calibration System (JimGibson)
    • Will start making waveguide loss measurements next week in Boulder. Should take about 1 month to complete.
  • Semi-Transparent Vane (STV) Calibration System (ThomasWilson)
    • Need only to get final report from Jesus Martin-Pintado.
  • Multi/Dual-Load (M/DL) Calibration System (Matt Carter)
    • No new news to report.

Weather (Ancilliary) Measurement Devices

JeffMangum has started working on actual hardware specification for weather instrument systems.

Calibration Needs for Cross-Correlation of the ACA and the Main Array (EdFomalont)

EdFomalont gave a brief report on the kinds of questions that he will discuss with the ACA group next Friday at Mitaka. The most relevant question for the calibration group is whether there is any significant gain for the ACA and ALMA arrays to be cross-correlated. The first-cut answer is "not enough in view of the large effort needed for this capability". See CalAca for EdFomalont summary. EdFomalont will discuss this issue further with NAOJ scientists while he is visiting Mitaka next week.

Comments from discussion of this issue:

MarkHoldaway: The primary reason for ACA/ALMA cross-correlation is to get <5% absolute amplitude calibration for both arrays.

Date of Next Phone Meeting

The next ALMA Calibration Group telecon will be 2005, November 10th 15:00 UT. Should we track the DST change and make the time 16:00 UT? Attendees agreed to stay at 15:00 UT to make it easier for our Japanese collegues to attend.

-- JeffMangum - 15 Oct 2005
Topic revision: r4 - 2005-10-18, JeffMangum
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