Photometry in VO Spectrum Model

[Tim Jenness]

On Mon, 23 Oct 2006, Anita Richards wrote:

>
>
> On Mon, 23 Oct 2006, Doug Tody wrote:
>> 
>> I can see that one might want to plot a spectrum in magnitude units in
>> a standard system.  A good question to consider however, is whether this
>> feature belongs in the user interface, where the spectrum is plotted in
>> whatever units the user prefers, or in the protocol.  This is similar to
>> displaying RA/DEC in sexagesimal units, while we use decimal degrees in
>> the protocol.  This sort of conversion is easily handled in the user
>> interface.
>> 
>
> Unfortunately it is not easy, that is the problem.  At least, I am assured by 
> optical astronomers that for highly accurate conversion you need a raft of 
> metadata and even to know the nature of the object.  That is also the case 
> for converting X-ray counts to physical units.

and antenna temperature in all its many forms (TA*, TR* etc) where people 
can't even agree on a standard nomenclature for all the efficiency terms 
that need to be known to convert kelvin to Jy.

-- 
Tim Jenness
James Clerk Maxwell Telescope