Although no further software development was planned, some
IUEDAC software was modified after the IUE project ended.
Most of these were Y2K-related changes and are listed below.
The changes were made because
the IUEDAC library was still being used for developing other
MAST-supported mission archives
including Copernicus and IMAPS.
The programs can basically be grouped into 3 categories: general,
IUE-specific, and Copernicus-specific.
Since the IUE project ended in 1997, it was felt unnecessary
to modify this group of programs. Projects modifying these
routines to work with other data sets however, may need to make the
appropriate date changes although its doubtful that many programs
in this category would be useful to other projects. The same applies
for the Copernicus-specific programs. Some of the low-level
programs and the FITS-handling routines however, are general enough to
be used by other projects, so these programs were modified.
The following changes were made:
2-digit dates are now assumed to refer only to the years 1900
through 1999 (i.e.,a date entry of 0 is assumed to
refer to year 1900). All other years must now be specified with
Tests for leap year were modified to include the special
case for years divisible by 400 (i.e., centuries NOT divisible by
400 are NOT leap years). Some programs which did have this test
were found to be incorrect (i.e., they assumed centuries not
divisible by 400 were leap years).
Starting Jan 1, 1999, a new format will be adopted for the DATE
and DATE-OBS FITS keywords which use 4-digit year entries.
As a result, the primary date conversion routine DATECONV was
modified to include a new mode called "newfits" which generates
the new FITS date format. Programs calling DATECONV
to create the DATE and DATEOBS keyword entries must be modified to
use this new mode at the end of this year.
Changes made to specific programs are listed below:
primary IUEDAC date-conversion routine
added 'newfits' mode, and use 4- (rather than 2-)
digit dates internally
convert yr,gmtday to dd/mm/yy format
fix leap year test and bug found for years 1900-1909 (program
mainly replaced by DATECONV)
extract IUE orbital elements
add comment about non-y2k compliance
calibrate gaussian extracted fluxes
use DATECONV for date conversions
convert dd-mon-yyyy to julian date and yr & day of yr
correct leap year calculation
convert dd-mon-yyyy to string yyddd.nnn
call DATECONV rather than the astron routine DATE_CONV(?)
convert julian date to [yr,dofyr,mon,d,h,m,s]
fix leap year calculation
converts [yr,d,h,m,s] to Julian date
add prolog information
generate FITS headers
call DATECONV instead of FDATE for date conversions
convert YYDDD dates to YYMMDD
correct leap year calculation and output dates
in YYYYMMDD format for other centuries (mainly replaced by DATECONV)
The following programs perform various date
calculations but were not modified because
they are specific to IUE data analysis:
MIDTIME (note incorrect century leap year test)
READDV (note incorrect century leap year test)
READELT (note incorrect century leap year test)
The IDL stacking routines (i.e., STACK, WSTACK, PSTACK,...)
used to coadd Copernicus spectral scans, use DATECONV to
create FITS header keywords, and will need to be modified to use
the new 'NEWFITS' mode starting 1/1/99.