UWS times

[Paul Harrison]

> On 2016-03 -23, at 08:52, Markus Demleitner <msdemlei at ari.uni-heidelberg.de> wrote:
> 
> Such considerations made us restrict timestamps in the VO to what
> DALI 1.0 says in 3.1.2 (cf.
> http://ivoa.net/documents/DALI/20131129/REC-DALI-1.0-20131129.html),
> which is (after a correction that comes in in 1.1),
> YYYY-MM-DD[Thh:mm:ss[.sss]].  So, the second reason I'd strongly
> argue UWS should make clear what kind of times in which form should
> be used is consistency with the rest of the VO.
> 
> I think the simplest way to make that happen would be by replacing
> all references to [std:iso8601] to DALI and specify, where
> appropriate, that the full form with T and time is to be used.

Hi,

After having thought about this a little more, I feel that it would be much better if DALI recommended that the Z timezone specifier were mandatory - timestamps in DALI can occur in various scenarios that are not as tightly constrained as a FITS file - e.g. in URL strings, and are possibly subject to being cut and pasted (or otherwise transferred) in and out of a variety of applications that might not know that the time was supposed to be UTC and in the absence of the timezone specifier legitimately interpret it as a local time - adding the Z would mean that it would be an error to make such an interpretation.

I am not sure why FITS decided not to follow ISO 8601 and omitted the Z - it is not as if it saved space….

Paul.