--- a/doc/ref/srfi-modules.texi 2014-03-20 20:21:21.000000000 +0000 +++ b/doc/ref/srfi-modules.texi 2016-06-24 18:57:59.088243245 +0100 @@ -2461,8 +2461,8 @@ @cindex UTC @cindex TAI This module implements time and date representations and calculations, -in various time systems, including universal time (UTC) and atomic -time (TAI). +in various time systems, including Coordinated Universal Time (UTC) +and International Atomic Time (TAI). For those not familiar with these time systems, TAI is based on a fixed length second derived from oscillations of certain atoms. UTC @@ -2494,18 +2494,12 @@ @cindex julian day @cindex modified julian day Also, for those not familiar with the terminology, a @dfn{Julian Day} -is a real number which is a count of days and fraction of a day, in -UTC, starting from -4713-01-01T12:00:00Z, ie.@: midday Monday 1 Jan -4713 B.C. A @dfn{Modified Julian Day} is the same, but starting from -1858-11-17T00:00:00Z, ie.@: midnight 17 November 1858 UTC. That time -is julian day 2400000.5. - address@hidden The SRFI-1 spec says -4714-11-24T12:00:00Z (November 24, -4714 at address@hidden noon, UTC), but this is incorrect. It looks like it might have address@hidden arisen from the code incorrectly treating years a multiple of 100 address@hidden but not 400 prior to 1582 as non-leap years, where instead the Julian address@hidden calendar should be used so all multiples of 4 before 1582 are leap address@hidden years. +is a real number which is a count of days and fraction of a day, in UT, +starting from -4713-11-24T12:00:00Z, ie.@: midday UT on Monday 24 November +4714 BC in the proleptic Gregorian calendar (1 January 4713 BC in the +proleptic Julian calendar). A @dfn{Modified Julian Day} is the same, +but starting from 1858-11-17T00:00:00Z, ie.@: midnight UT on Wednesday +17 November AD 1858. That time is julian day 2400000.5. @node SRFI-19 Time