VOUnits RFC

[Arnold Rots]

I was pondering this question from its flipside:
If Norman introduces MyWeight, how does the user know what value
Norman actually used?
Some canonical value? his preferred weight? his weight of the day?
Is that value (whatever it is) published anywhere?
The tropical year is another example.

I shudder a bit when I imagine the confusion that may arise.
Nevertheless, I agree that option 2 is probably the lesser of many evils
- though it would be good if authors would have a mechanism to define
their cutesy units.

  - Arnold

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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 cfa.harvard.edu
USA
http://hea-www.harvard.edu/~arots/
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On Mon, Jul 29, 2013 at 4:38 PM, Rob Seaman <seaman at noao.edu> wrote:

> Hi Norman,
>
> I must admit to not having had the chance yet to review the current
> version of the document, so perhaps this is addressed.
>
> > I think 2 is a problem, but I don't think it's a bad problem.  That is,
> I more and more confidently agree with Rick in his message of this morning,
> that you've lost meaning that might be important down the line, if you lose
> the link between this unit and the mass of jupiter.  OK, there's a problem
> if the receiver doesn't recognise 'jupMass', but there are mitigation
> strategies (some listed by Rick), one of which is to look at the
> documentation, and discover "ah, _this_ exoplanet database recognises the
> non-standard unit 'jupMass', so I can use that in my requests to it".
>
> A more fundamental issue is that often measurements are calibrated in
> terms of other measurements.  Quoting something as 1.5 jupMass might not
> just be a handy way to provide a sense of scale, but it might be that as
> measurements are refined of what the mass of Jupiter actually is, that the
> number quoted (in the table or what have you) ought be adjusted to suit.
>  Examples abound such as the Hubble constant, etc.
>
> Rob
>
>
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