VOEvent 1.1 new draft with STC elaboration

[William Thompson]

Arnold Rots wrote ...

> Correction:
> 
> Assuming that times will typically be corrected for pathlength delay (please speak up if that is not the plan), times will be Heliocentric, while some of the solar spatial systems are intrinsically heliocentric, others topocentric.
> I suggest the following standard systems:
> 
>   UTC-HPC-TOPO
>         Describes raw observational data
>   UTC-HELIO-HPC-TOPO
>         For time-corrected observational data
>   UTC-HGC-HELIO
>         Suitable for reporting solar events
> The following seem useful:
>   UTC-HELIO-HEEQ-TOPO
>   UTC-HELIO-HCC-TOPO Are there any among these that you don't expect to be used at all? Are there any among these that you don't expect to be used in VOEvent? Are there others that you expect to be used? 

I've talked to some of the people here involved in flare notification.  We agree 
that flare locations are usually given in heliographic coordinates, but these 
are Stonyhurst coordinates, different from the Carrington HGC coordinates 
referred to above.  Perhaps Stonyhurst Heliographic coordinates should be 
referred to as HGS?

I don't believe that the reported times of flares are generally corrected to 
heliocentric time.

HPC coordinates are also sometimes used for reporting events, such as flares, 
usually in arcseconds.

Helioprojective-radial (HPR) coordinates, i.e. polar angles, are used for 
reporting coronal mass ejections.

I doubt that HCC coordinates would be used.

-- 
William Thompson
NASA Goddard Space Flight Center
Code 612.1
Greenbelt, MD  20771
USA

301-286-2040
William.T.Thompson.1 at gsfc.nasa.gov