2005-12-08 ALMA Calibration Group Telecon Agenda and Minutes
ALMA Calibration Group Telecon
  • Date: December 8, 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 2006-01-15 Follow-up on October 2005 ASAC report comments and questions. closed JeffMangum edit
JeffMangum 2006-03-15 Comments to ACA calibration issues resulting from ACA System Review. closed JeffMangum edit


Agenda and Minutes

NOTE: Discussion from the telecon is shown in italic.

Attendees

  1. JimGibson
  2. RobertLucas
  3. JeffMangum


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 January 13, 2006 so that everyone will have time to read them by our our next telecon.


Amplitude Calibration Subsystem Development Reports

  • Berkeley Absolute Flux Calibration System (JimGibson)
    • Waveguide loss measurements using Popovic(?) lab in Boulder have been made. Can now proceed with data reduction.
    • Will submit report on calibration system results in early January 2006.
    • Atmosphere likely to be the largest contributor to overall measurement uncertainty.
  • Semi-Transparent Vane (STV) Calibration System (ThomasWilson)
    • Need only to get final report from Jesus Martin-Pintado. Reminder has been sent.
  • 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)

The most relevant question within this topic 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 is iterating on this issue further with NAOJ scientists.

Please see the ACA Calibration Plan under discussion at the ACA System Review Today in Tokyo. Please post comments/discussion on this issue to the CalAca wiki. In order to close this issue by our next telecon, please comment by January 15, 2006.


ASAC Comments on Calibration in ALMA Science Requirements

See the October 2005 ASAC Report, section 4 (their Charge 2). The ASAC would like clarification on a few issues regarding amplitude calibration stability and polarization and primary beam calibration requirements. Please post comments to this issue on the CalAsac wiki. In order to close this issue by our next telecon, please comment by January 15, 2006.


Date of Next Phone Meeting

The next ALMA Calibration Group telecon will be 2006, January 19th 15:00 UT (NOTE: This is 1 week beyond our regularly-scheduled date to avoid conflict with the AAS meeting).

-- JeffMangum - 08 Dec 2005

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Topic revision: 2005-12-08, JeffMangum
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