[obs-tap]:updates on the Proposed recommendation + new document

[Arnold Rots]

Just two quick comments. Both highlight how this standard is still
heavily slanted toward optical images.

  - Arnold

Mireille Louys wrote:
[ Charset ISO-8859-1 unsupported, converting... ]
> Dear Arnold, Dear all,
> 
> 
> > o_stat_error is an interesting case. Since our unit is counts, the
> > proper value would be "POISSON"; I realize that that is not a double,
> > but what else can we give as a value?
> >
> This was meant only for quantitative estimation of the error and does  
> not cover the statistical properties of the signal.

I realize that, but the problem is that one can't give a single
quantitative value in the case of Poisson noise. However, identifying
it as Poisson does immediately provide the value for each point in the
image.

> 
> >>
> >> Ian Evans noticed the inconsistency in units for spatial resolution
> >> between the Tables 1, 4, 5, and 6 (arcsec vs. deg); what should it be?
> >> I assume deg?
> >> See also s_stat_error in Table 5.
> >>
> We agreed in previous iterations to have resolution and errors in a  
> convenient and handy unit: arcsec for space and s for time , for  
> instance because they are usually given that way in instrument  
> descriptions and scientific papers.

Too bad the same reasoning was not applied to the EM units; when I
complained about the requirement to use m, I was told that it's only a
number seen by software that can easily be turned into a more
convenient unit for display to the user :-P

> 
> 
> 

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Arnold H. Rots                                Chandra X-ray Science Center
Smithsonian Astrophysical Observatory                tel:  +1 617 496 7701
60 Garden Street, MS 67                              fax:  +1 617 495 7356
Cambridge, MA 02138                             arots at head.cfa.harvard.edu
USA                                     http://hea-www.harvard.edu/~arots/
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