Package: bsdmainutils Version: 9.0.6 Severity: wishlist File: /usr/bin/ncal Tags: upstream
Dear Maintainer, I was interested in adding support to cal/ncal for the Jewish and Islamic lunar calenders (specifically the Umm al-Qura Islamic calender standardized in Saudi Arabia), and as there is a fair bit of math involved, asking if such a patch would be considered (with no guarantee) in advance. Islamic calender ---------------- The days are purely lunar, with a "year" being exactly 12 moons. These moons are differn't from a rotation of the Moon around the Earth, with details (look at the source) here: http://www.staff.science.uu.nl/~gent0113/islam/ummalqura.htm Jewish calender --------------- A modified lunar calender, there is a leap month (Adar) entered according to the metonic cycle. There are also some special leap day(s) rules discussed here: https://en.wikipedia.org/wiki/Hebrew_calendar#Rosh_Hashanah_postponement For current day calculation --------------------------- Days in Judaism and Islam start at sunset. The user may either provide a latitude and longitude[1], or by default the coordinates of Jerusalem or Mekkah will be used, respectfully. Existing timezones cannot be used (the latitude where that time would be the mean solar time) because sunsetcalculations requie a latitude. For days in with the artic or antartic circle in which the sun either does not set or does not rise, solar midnight will be used (days are not 24 hours long). Rounding errors --------------- The solar declination calculation is subject quite a bit to rounding errors. When using IEEE-754 64-bit the avr-libc library reports a 4.8 minute drift of solstice per year, which becomes significant with the historical Jewish calender (but not the modern Islamic calender). So if historical Jewish dates are desired, libquadmath should be used. Liberty equality fraternity or death, Shawn Landden [1]Or, optionally, only a latitude (and get the longitude from the mean solar time of the current timezone)? -- System Information: Debian Release: 8.0 APT prefers unstable APT policy: (500, 'unstable'), (1, 'experimental') Architecture: amd64 (x86_64) Foreign Architectures: musl-linux-arm64 Kernel: Linux 3.2.0-4-amd64 (SMP w/1 CPU core) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) Versions of packages bsdmainutils depends on: ii bsdutils 1:2.25.2-6 ii debianutils 4.4+b1 ii libc6 2.21-0experimental0 ii libncurses5 5.9+20140913-1+b1 ii libtinfo5 5.9+20140913-1+b1 bsdmainutils recommends no packages. Versions of packages bsdmainutils suggests: ii cpp 4:5-3 pn vacation <none> ii wamerican [wordlist] 7.1-1 ii whois 5.2.7 -- no debconf information -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
