UCDs in SpectrumDM

[Frederic V. Hessman]

On 23 Jun 2007, at 8:52 pm, Jonathan McDowell wrote:

>
> Andrea,
>
>  I guess I don't feel that
>    phot.flux.density;em.wl,stat.max
>  (and similar) are 'cumbersome' - I find them much easier
>  to understand than extra custom-crafted UCDs like ..perWave.
>  I feel that em.wl, em.freq, etc. are naturally adjectives as well as
>  nouns

>  For em.*: in the context of the doc, this is a shorthand for
>  (EITHER em.wl OR em.freq OR em.energy).

I confess that I have a hard time with all of these solutions, since  
they are workable only if the assumptions behind them are clearly  
defined (and who is going to garantee that someone teaches a computer  
correctly?).

In order to manipulate the numbers, the VO apps are going to have to  
deal with the units anyway, so I'd prefer one of two extreme solutions:

1.	em.flux				THAT'S IT!  Whether it's W/m^2/micron or Jy or photons/ 
cm^2 .... can only be known by looking at the units.

or

2.	Pendanticism, e.g.	W/m^2/micron =  
em.energy;stat.perSqrMeter;stat.perTime;stat.perWavelength


I know these comments are late - so you can promptly delete this  
email - but these seem much more workable solutions.

Rick

------------------------------------------------------------------------ 
------------------------
Dr. Frederic V. Hessman     Hessman at Astro.physik.Uni-Goettingen.DE
Institut für Astrophysik          Tel.  +49-551-39-5052
Friedrich-Hund-Platz 1         Fax +49-551-39-5043
37077 Goettingen                 Room F04-133
http://www.Astro.physik.Uni-Goettingen.de/~hessman
------------------------------------------------------------------------ 
-------------------------
MONET: a MOnitoring NEtwork of Telescopes
http://monet.Uni-Goettingen.de
------------------------------------------------------------------------ 
-------------------------


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.ivoa.net/pipermail/semantics/attachments/20070625/a58cd120/attachment-0003.html>