2006-08-17 ALMA Calibration Group Examples Document Review

Table of Contents:


  1. RobertLucas
  2. JeffMangum
  3. Sakiuchi
  4. Shigehisa Takakuwa
  5. BaltasarVilaVilaro
  6. Jack Welch

Review of Optics Calibration Example

  • See comments on CalExamples wiki.
  • Comments by JeffMangum :
    • Surface Setting and Transmitter Holography Sections: Should simply refer to AEG Holography Report and Baars, Lucas, & Mangum (2006, IEEE A&P Magazine, in review). All of the information currently listed is contained in these documents.
    • Transmitter Holography: In fact one does not want to average multiple maps to improve signal-to-noise. Since there are at least temperature-dependent variations from map-to-map, and signal-to-noise is sufficient with one map, averaging is not desirable.
    • Celestial Holography: Phase-retreival holography is also called Out-of-Focus (OOF) beam maps.
    • Interferometric Holography: Since low resolution maps will be used in practice, while high resolution maps will be used mainly during commissioning, discussion order of these two types of interferometric holography maps should be switched. Note too that high resolution map measurements can really only be done using the Orion SiO maser source.
    • Phase-Retrieval Holography: Should note that this will likely only be used during commissioning, given the need for very strong sources and the option to do interferometric holography.
    • Focus Curves: I believe that one will generally want to scan fast rather than point-and-integrate for these measurements to avoid atmospheric fluctuations.
    • Single Dish Focus Measurement: "cross-correlation" should be "autocorrelation".
    • Interferometric Focus Measurement: RobertLucas comment regarding utility of 16x16 interferometric holography maps applies to this problem.
    • Rx Feed Setting: Rewrite to emphasize use of 16x16 interferometric holography maps to derive receiver feed setting (see RobertLucas comment).
    • Appendix: Please compare sigma_{snr} equation to those quoted in AEG Holography Report.
  • Comments by RobertLucas :
    • See also comments on CalExamples wiki page.
    • Goals: Add feed illumination of subreflector to list of measurements.
    • Focus Curves: For interferometric measurement, it is better to make 16x16 holography maps to derive focus and feed offsets.
    • Receiver Feed Measurement: The "single beam alignment" section should be replaced with reference to the 16x16 holography map used for the focus curve measurement. Note, though, that the beam map technique described in the current text will be required for antenna commissioning.

Next Review

On 2006/09/21 we will review the ACA calibration example document.

-- JeffMangum - 17 Aug 2006
Topic revision: r3 - 2006-08-17, JeffMangum
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