2007-07-12 ALMA Calibration Group Telecon Agenda and Minutes

ALMA Calibration Group Telecon
  • Date: July 12, 2007 (Thursday)
  • Time: 14:00 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  

Agenda and Minutes

NOTE: Discussion from the telecon is shown in italic.


  1. JeffMangum
  2. Richard Hills
  3. BojanNikolic
  4. Lars-Ake Nyman
  5. Alison Peck
  6. JohnRicher
  7. LeonardoTesti
  8. AlWootten

Calibration Examples Status

Still waiting on final versions of bandpass (RobertLucas), delay (RobertLucas), polarization (EdFomalont), optics (BaltasarVilaVilaro), and ACA calibration issues (EdFomalont) calibration examples. See CalExamples wiki for further information.

Calibration Sequence Development

Will begin process of turning CalExamples into calibration "sequences" during 2007Q3. Need to first meet with Computing IPT to figure out which Computing IPT personnel will be available to participate in sequence development.

Noted by Richard Hills: Computing and Science IPTs need to get to work on Sequence development soon. AlWootten notes that extended lifetime of the ATF affords an opportunity to develop and test Sequences before they are needed in Chile.

Amplitude Calibration Subsystem Development Reports

  • Berkeley Absolute Flux Calibration System (Jack Welch)
    • No report.
  • Semi-Transparent Vane (STV) Calibration System
    • Received final report on 2007/07/11. This item is now officially closed.
  • Multi/Dual-Load (M/DL) Calibration System (Ferdinand Patt)
    • Ferdinand Patt noted before the meeting that the robotic arm system for the calibration device passed its FDR (with a few minor issues to resolve). Company building robotic arm is NTE (Spain). Also, Ferdinand expects the load test report from IAP (Institute doing the test for ALMA) to be available by the end of this week.

Weather (Ancilliary) Measurement Devices

In December 2006 JeffMangum submitted weather station instrumentation (RH, P, T, and wind) RFQ documentation to NRAO procurement system. After having reviewed information received from bidders and consulted with Calibration Group (see CalAncillary for discussion), on 2007/03/21 JeffMangum submitted purchase information to RobertLaing for procurement.

Leonardo Testi continues to push purchase through ESO purchasing system. Will likely obtain a loaner set of weather devices from Vaisala to allow us to test the integrated system either at ESO or NRAO.

Oxygen Sounder

JohnRicher has developed a contact with one of the companies that produces O2 sounders. With BojanNikolic, they are investigating issues related to operating such a device at 5000 m, among other things.

One of the companies that produces O2 sounders has recently been doing a study for a site at 3300m asl and so they have a good idea of expected performance at high elevations. They have told us that they expect accuracy of about 0.5K in the first kilometre of the atmosphere and about 1K accuracy higher up. This is a bit better than previously expected and is likely to be good enough for atmospheric phase correction purposes.

There is, however, one obstacle. The algorithm to invert the radiometer measurements to a vertical temperature profile is based on a neural network and requires a large training set to function properly. We have been told that something like 10 years of daily radiosonde launches are required. We currently looking at what data are available in the vicinity of the ALMA site. -- BojanNikolic

Question regarding purchasing process. Since budget in on NRAO side of the ALMA budget, what are requirements for purchasing? Likely requires an RFQ with bid evaluation. JohnRicher and BojanNikolic will continue to investigate potential vendors and devices.

Solar Observations and Calibration

MarkHoldaway has written a draft document on Calibration of Solar Observations. We discussed this document at our last telecon. Few revisions are needed. MarkHoldaway will update and submit final version within the coming few weeks.

Date of Next Phone Meeting

The next ALMA Calibration Group telecon will be 2007, August 16th 14:00 UT (shifted by +1 week).
-- JeffMangum - 12 Jul 2007
Topic revision: r5 - 2007-07-30, JeffMangum
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