On Apr 22, 2005, at 7:14 PM, Roy Williams wrote:
> There are two things being discussed here: Scientific Time and what we
> can call Human Time or Office Time.
The name "Civil Time" is proving to be pretty standard in the UTC "deliberations".
> The former has careful astronomical coordinates around it, and we are
> using STC.
> For the latter I would suggest ISO 8601, which is what the registry
> harvesting is using.
I don't have ISO 8601 in front of me, but from the various discussions surrounding the Y2K remediation wars I suspect that its connection to UTC is only tenuous at best. There is the business of appending "Z" to indicate Zulu time, but Zulu is really a specification of GMT in "zone" (so called standard time) parlance. And, of course, an implicit assumption is that such a timestamp is valid at all locations. I suspect we could find examples for why this might not be the case in civil usage as well as scientific usage.
That said, current astronomical usage, e.g., FITS, does rely on ISO 8601 (a subset, at least) to express UTC (loosely, at least) for utility purposes (both civil and scientific) with topocentric observatory locations (or locationless specifications of time).
Even for purely utilitarian purposes, the astronomical community faces the prospect of having to distinguish between situations in which the Earth orientation nature of time is important versus situations in which the Civil (clock on the wall) nature of time is more important. We may not be able to rely on a single time scale continuing to express both.
Rob Seaman
NOAO
Received on 2005-04-23Z03:37:39