From William.T.Thompson at nasa.gov  Tue Oct 13 15:04:25 2009
From: William.T.Thompson at nasa.gov (William Thompson)
Date: Tue, 13 Oct 2009 15:04:25 -0400
Subject: [fitswcs] Draft WCS Paper V: Time; Verion 0.73
In-Reply-To: <200909301855.n8UItAmC019852@xebec.cfa.harvard.edu>
References: <200909301855.n8UItAmC019852@xebec.cfa.harvard.edu>
Message-ID: <4AD4CF39.7000903@nasa.gov>

Here are some comments on the latest draft.

* In section 3.3.4, the keyword TREFDIR is mistakenly referred to as the Time
   Reference Position.  It should be Time Reference Direction.

* In section 3.3.5, reference is made to DE200 and DE405.  I believe that the
   current standard is DE421.

* I put together those example FITS files rather hurriedly, and missed the fact
   that the value of TTYPE should be 'UTC' rather than 'TIME'.  It would be
   better to change to CTYPE4='UTC' instead of saying

CTYPE4  = 'TIME    '       / Might also have been 'UTC'

* The CTYPE3 keyword is repeated in Tables 5 and 6.

* It might be useful to put in a comment after the keyword PC4_2 along the
   lines of

PC4_2  =       -0.00832947 / Relationship between time and Solar X

* In Table 6, one can also add a comment after PC4_3

PC4_3  =        0.00109510 / Relationship between time and Solar Y


Arnold Rots wrote:
> FITS WCS Paper V: Time
> ======================
> 
> A new draft is available for comment
> ------------------------------------
> 
> 
> You may find a new draft (Version 0.73) and some useful links at:
> 
>     http://hea-www.harvard.edu/~arots/TimeWCS/
> 
> Progress has been made since the first draft was put out for comment,
> almost 6 months ago, but there is still work to be done.
> As before, you will notice editorial comments printed in red.
> 
> The intent is that this discussion be carried on through
> fitswcs at nrao.edu even though this announcement also goes out on
> fitsbits.
> 
> 
> Enjoy!
> 
>   - Arnold Rots
> 
> 
> --------------------------------------------------------------------------
> 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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-- 
William Thompson
NASA Goddard Space Flight Center
Code 671
Greenbelt, MD  20771
USA

301-286-2040
William.T.Thompson at nasa.gov

(Note changed email address)