VOUnits RFC

[Norman Gray]

Arnold,

On 2013 Jul 26, at 20:45, Arnold Rots <arots at cfa.harvard.edu> wrote:

> I think I would definitely deprecate ta and Ba, not sure about min.
> h and yr are fine, as far as I am concerned.

I'll make suitable adjustments.

> Personally, I find ha a bit obscure and tend to think of it as representing
> hectare.
> I would prefer cy.
> That makes me wonder, what is the SI symbol for are? a or are?

It looks like it doesn't exist.  The SI brochure, table 6 ("Non-SI units accepted for use with the International System of Units") says that the unit is 'hectare', symbol 'ha', so it doesn't acknowledge this as being 100 'ares'; also it mentions that "The unit hectare, and its symbol ha, were adopted by the CIPM in 1879".  Bit of an anomaly, really, and aside from some arcana mentioned on the Hectare wikipedia page, it sounds as if no other prefixes are sane.  Isn't today quite the day for the arcana?

I've been sitting here trying to work out some situation where a flux of small inductances makes some sense, so that someone could use units of aH/(ha.ha).  And couldn't.

SI Table 6, incidentally, is the same table that mentions days, hours and minutes, plus angular measure, litres and tonnes.

All the best,

Norman


-- 
Norman Gray  :  http://nxg.me.uk
SUPA School of Physics and Astronomy, University of Glasgow, UK