Registry in RSS
seaman at noao.edu
Thu Jan 14 06:08:38 PST 2010
On Jan 13, 2010, at 12:43 PM, Mike Fitzpatrick wrote:
> Not quite what I meant: I know there are numerous feeds for actual "VOEvents", what I was proposing was a feed for "VO Events" like the availability of a new resource, overlaying the voevent infrastructure, e.g. not that the Catalina Sky Survey found an object, but that the CSS is now a broker for "Bob's-really-cool-GRB-followup-on-his-GalileoScope" program.
> The heretical part is that I see 'events' as a type of message, and little difference between a GRB "stream" subscription, a "KBO" one, and a "general msg" one. Is the idea "there is something new on the sky" really that much different than "there is something new in the Registry"? Note I'm not quite yet suggesting IVOA address these cross-WG issues, neither do I see a need for an emerging discussion on a new protocol for Tweet/Rss that shares many similarities (at least wrt the 90/10 rule) with existing standards.
As a timely example of such an astronomical, but not celestial, event see the appended IERS bulletin published this morning. This shares numerous features with the mechanism that Mike is describing. It cries out for a semantic representation (rather than "natural language") - such as an XML standard like VOEvent. (And an early debate in the WG was whether "event" had a strictly celestial meaning or also included, for instance, the computer science definition of events.)
Further, it is prospective, rather than retrospective - VOEvent has to be able to describe events that haven't happened yet, in addition to reports from the historical record. A repository of past bulletins is implicit. It has an author (Gambis) as well as a publisher (IERS). Delivery is transport neutral. There are contingent metadata like the publication date and the publisher's contact information. The message relies on several widely promulgated standards, most notably UTC. Etc.
A field of inquiry is layered on many such streams of events, whether "event" is defined scientifically, technically or simply logistically. Does it make sense to invent a new representation and transport protocol for each stream? More likely there will evolve a small number of options that satisfy that 90/10 rule. Some applications are so idiosyncratic or tightly bound that they fall into the 10%. But too often a 90% project chooses a 10% solution for no good reason - or they choose a too broad solution (such as the text file below) that is no real solution at all.
Is Mike's heresy a high priority for IVOA attention? I don't know, but it does seem like a good topic for the TCG workshop whenever and wherever that may ultimately be held.
Begin forwarded message:
> From: IERS EOP Product Center <services.iers at obspm.fr>
> Date: January 14, 2010 5:44:21 AM MST
> To: adresc1 at arcas.obspm.fr
> Subject: Bulletin C number 39
> INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS)
> SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE
> SERVICE DE LA ROTATION TERRESTRE
> OBSERVATOIRE DE PARIS
> 61, Av. de l'Observatoire 75014 PARIS (France)
> Tel. : 33 (0) 1 40 51 22 29
> FAX : 33 (0) 1 40 51 22 91
> Internet : services.iers at obspm.fr
> Paris, 14 January 2010
> Bulletin C 39
> To authorities responsible
> for the measurement and
> distribution of time
> INFORMATION ON UTC - TAI
> NO positive leap second will be introduced at the end of June 2010.
> The difference between Coordinated Universal Time UTC and the
> International Atomic Time TAI is :
> from 2009 January 1, 0h UTC, until further notice : UTC-TAI = -34 s
> Leap seconds can be introduced in UTC at the end of the months of December
> or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every
> six months, either to announce a time step in UTC, or to confirm that there
> will be no time step at the next possible date.
> Daniel GAMBIS
> Earth Orientation Center of the IERS
> Observatoire de Paris, France
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