The Napkin Representation

[Rob Seaman]

On Jul 3, 2007, at 8:23 AM, Anita M. S. Richards wrote:

> It seems to me that there are two approaches here - one from the  
> point of view of people interested mainly in the time domain  
> behaviour of variable or erruptive sources, or of data (e.g. Solar)  
> where the viewpoiint changes as a function of time.  The other  
> aspect is those of us who are venturing into the time domain as  
> high angular resolution or sensitivity reveals variability or  
> allows us to study it - alongside other multi-wavelength properties.

Yes, although many more than two POVs.  The time domain, particularly  
short latency transient alert response, is an incredibly rich and  
growing research area.

> Two issues - if we are allowing magnitudes, can we also allow X-ray  
> counts?

Yes.  Nothing magical about Pogson's magnitudes.

> (I would like to see all data calibrated in physical units, but it  
> ain't, and for the history of variable objects, when there are very  
> few X-ray telescopes, we ahve to take what we can get).

The argument here is with IAU Commission 6.

> Secondly, typically I want to label data with the waveband (radio)  
> and with the observing wavelength or wavelength interval (or better  
> still frequency, but that's not important) - there might be several  
> observations at one wavelength and several at another.  Would this  
> have to be in separate data sets with the wavelength information in  
> a header-type structure, or in a 3rd column?  If in a header-type  
> structure, i.e. keepinf 2 columns only, then it is even more  
> important to maintain a header structure which existing VO tools of  
> all kinds will recognise.

Right.  It is in the combination of multiple time series that the  
proper choice of representation becomes most critical.

> I am very very wary of additional formats; this has been suggested  
> be fore but the beauty of VOTable is precisely that it is very  
> simple and the average astronomer in the wild can get to grips with  
> it, whereas the full complexity of XML scares us off.  More  
> imporantly, VOTable is so widely used that there are many tools in  
> both astronomy adn solar physics which use it.

It may be that VOTable has reached critical mass and should be deemed  
the obvious choice of serialization.  The more basic question is  
whether SSA time series are the obvious choice of DM.

Rob