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New version ISO 8601:2005 released 2005-04-01

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  • John Hynes
    The newly released version of the ISO Standard for Representation of dates and times (8601:2005) includes a new section 5.3.5. Based upon Resolution B7 on the
    Message 1 of 3 , Mar 31, 2005
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      The newly released version of the ISO Standard for Representation of
      dates and times (8601:2005) includes a new section 5.3.5. Based upon
      Resolution B7 on the use of Gregorian Dates by the XXIIIrd
      International Astronomical Union General Assembly, the new standard
      specifies that decimal time of day be represented as a fractional day
      added to the ordinal day of month, or alternately to the ordinal day
      of week or ordinal day of year. Here is the text of the new section:

      ---------------------------------------------
      5.3.5 Representation of Decimal Time of the Day

      Time of the day may be represented as a decimal fraction of the day.
      If a decimal fraction is included, lower order components (if any)
      shall be omitted and the decimal fraction shall be divided from the
      integer part by the decimal sign specified in ISO 31-0: i.e. the comma
      [,] or full stop [.]. Of these, the comma is the preferred sign.

      The number of digits in the decimal fraction shall be determined by
      the interchange parties, dependent upon the application. The format
      shall be [DD,DD], with as many digits as necessary following the
      decimal sign. A decimal fraction shall have at least one digit. At
      least three digits are recommended.

      a) A specific year, month and day of the month and a decimal fraction
      of the day
      Basic format: YYYYMMDD,DD EXAMPLE 20050401,123
      Extended format: YYYY-MM-DD,DD EXAMPLE 2005-04-01,123

      b) A specific year and day of the year and a decimal fraction of the day
      Basic format: YYYYDDD,DD EXAMPLE 2005091,123
      Extended format: YYYY-DDD,DD EXAMPLE 2005-091,123

      c) A specific year, calendar week and day of the week and a decimal
      fraction of the day
      Basic format: YYYYWwwD,DD EXAMPLE 2005W135,123
      Extended format: YYYY-Www-D,DD EXAMPLE 2005-W13-5,123
      ---------------------------------------------

      The new version of the ISO 8601 standard is being released today,
      2005-04-01.000. It is being recommended that this new representation
      be immediately used for representing UTC times of the day, in order to
      more easily distinguish them from local times of the day. Major
      software manufacturers, including Microsoft and Apple, and several
      Linux distributors, have promised to include support for the new
      standard in software updates for their platforms.

      Computer enthusiasts in Europe have already embraced the new time
      standard, as reported on Slashdot, although it seems to be largely
      ignored in English-speaking countries. The European Software
      Consortium has announced that that they will use the new standard as
      the default timestamp format for data interchange. In addition, the
      Swatch watch company has promised to add support for decimal
      representation of UTC in addition to "Biel Mean Time" in their .beat
      line of watches, using a comma for UT and @ for BMT.
    • John Steele
      I m sure astronmers everywhere would have preferred Julian Days, ie 245 3461.500 John Hynes wrote: The new version of the ISO 8601 standard is
      Message 2 of 3 , Apr 1, 2005
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        I'm sure astronmers everywhere would have preferred Julian Days, ie 245 3461.500

        John Hynes <john@...> wrote:

        The new version of the ISO 8601 standard is being released today,
        2005-04-01.000. 
      • John Hynes
        ... Astronomers also use Gregorian dates, in year-month-day order, with the fractional day added to the ordinal day of month. For instance, the standard epoch
        Message 3 of 3 , Apr 1, 2005
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          --- John Steele <johnmsteele@y...> wrote:
          > I'm sure astronmers everywhere would have preferred Julian Days, ie
          > 245 3461.500

          Astronomers also use Gregorian dates, in year-month-day order, with
          the fractional day added to the ordinal day of month. For instance,
          the standard epoch J2000.0 is often represented as 2000 January 1.5,
          which would be 2000-01-01,5 in ISO format. I can provide many
          examples online. Also, NASA and NORAD publish epoch dates of orbital
          elements of artificial satellites as ordinal dates with fractional day
          added, e.g. the same date is represented as 00001.50000000. (Still
          with two-digit year, unfortunately.) It would make sense to
          incorporate this practice by astronomers into ISO 8601. Although the
          month is usually spelled out or abbreviated, the month number is also
          used sometime. The ISO standard does cover decimal fractions of
          hours, minutes and seconds, but not days.

          I suppose that Julian Dates could be added to the ISO 8601 standard,
          but that would seem unnecessary, since they are represented simply as
          a single decimal number. It would be a short section. I think that
          fractional day s are used by astronomers, instead of HMS, for ease in
          calculations, including the converstion to/from JD/MJD. Julian Days
          and Julian Dates, as well as Modified Julian Dates, already are
          covered by a standard, IAUGA XXIII Resolution B1.

          And if anybody hasn't figured it out by now, April Fool! I figured
          that this group might get a kick out of it. :)

          John
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