Summary of dicussion during chop-nod analysis skypecon of May 14, 2008

Tristan, Hiroko, Martin, Giles, Lero

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analysis of M82 data

Jackie and Lero are collaborating on deriving FAZO, FZAO.

Lero has made more progress on April data (spreadsheet mailed to Giles).  
He finds that sometimes the "fitgauss" fits work and sometimes they don't.  
When they don't, he interpolates FAZO and FZAO from adjacent files.

We decided that we can combine data from different runs into one big 
sharpcombine fit as long as the i.p. is the unchanged.  So we can combine 
data from Feb 07, early-April 07, and late-April 07.

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Tristan work on DG Tau:

He has reproduced results from Giles' DG Tau memo of May 2007

He is going after the Aug 2007 DG Tau data next

He is doing fitgauss and finds it works well, but he has to use the 
"fsigma" option to constrain the width.  fitgauss works most of the time.

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Giles work on L 1527 (Nov. 2007 run):

He has finished the pointing corrections (all FAZO, FZAO in hand).

Fitgauss works well ~75% of the time.  (Giles' criterion for claiming that 
fitgauss "works" is that it gives a reasonable value, and that furthermore 
this value agrees reasonably well with the value obtained "by eye".)  For 
the cases where fitgauss gives garbage values, interpolation is used (as 
for M82, see above).

The fitgauss failures seem correlated with large DC offsets.

The b option seems to have no effect on the results obtained

Giles is also using "fsigma", which helps a lot

Hiroko suggested using ix0 and iy0.  (initial guesses for peak location in 
pixel space).  Giles thinks he already tried that, but is not sure.  
Anyway, the pointing corrections are good now, at least for a first 
iteration.

Giles points out that only 55% of the 144 polarimetry pixels are usable 
for polarimetry, while 77% of the total of 288 SHARP pixels are good.  
For the August 2007 and Feb 2007 data, these numbers seem to have been 
significantly higher.

Hiroko will confirm whether it is "220/288 or 220/384" in her Fall 2007 
RGM memo.  The info in this memo may provide clues to this problem of 
changing numbers of bad pixels.

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We should all keep in mind the possibility of showing our results in the 
CSO renewal proposal.

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not discussed on skypecon: sharpcombine on mac