[mmaimcal]Re: [Almasci] Re: WVR treatement in System Design Description

[Al Wootten]

Larry D'Addario wrote:
> Richard,
> 
> I won't be able to respond in detail to all your points right now, but
> the bottom line seems to be very little change from my numbers.  I am
> happy to drop the language in the System Design Document about the
> best reported WVR residual, using instead your estimate of the
> performance.  You are merely suggesting that
> 
> a.  The 2% scaling error should be added in quadrature to the
> radiometer noise error; and
> 
> b.  We allow an additional 10 microns for non-water-vapor
> fluctuations, also in quadrature to the other terms.
> 
> I do think that the last value may be optimistic; it implies that the
> fluctuations are only ~5 ppm compared with the total dry air delay at
> Chajnantor.  I also think that the 2% scaling error is optimistic; I
> have never seen a basis for it, and you seem to agree when you say
> that it is "less conservative."  Nevertheless, I'll accept these
> numbers because I don't have any better ones.  
> 
> This gives, as you say, 73.3 fsec total under the adopted conditions
> for the 5th percentile, compared to the 68 fsec that I got without the
> last term, and compared with 83 fsec as the best-reported WVR residual. 
> This range is not significant.
> 
> What I would appreciate is some document (other than an email!) in
> which this is written up and to which I can refer.  IMHO, a set of
> powerpoint slides doesn't count.  When can we have this?  If it needs
> to be written, can you provide a title, author(s), and document
> location (either an ALMA document number, or the name of a memo series
> or journal to which it will be submitted) so that I can reference it
> as "in preparation"?
Dear Richard, Larry, and all.

One course of action would be to incorporate the appropriate words in 
the 'Calibration of ALMA' document which we submitted in August and 
which has had no comments posted.  It has not been through the approval 
process (a CRE--it is the update to the Project Book Chapter 3, already 
approved) because it didn't have the proper Microsoft Word formatting, 
with the logo.  Stacy has kindly fixed that for us and it will be pushed 
along in the approval process soon.  I need to go over Stacy's copy for 
corrections.  The proper ALMA reference for this is:

Calibration Specifications and Requirements
ALMA-90.03.00.00-001-A-SPE Version: B  Status: Draft 2003-08-07

The original copy is somewhere on almaedm, or more easily found at:
http://www.cv.nrao.edu/~awootten/mmaimcal/CalibrationofALMA3.pdf

Clear skies,
Al