An application that generates a simple calendar based on a given date, from the year 1500 to the year 2000 and a bit. It also gives the Julian Day number for the given date and vice versa. This application shows a 50% reduction, on the screen, of what will come out on paper.
This application was written at the request of a nice fellow, D.M. Loveridge, who paid his shareware fee. As a historian, he wanted to be able to reconcile days and dates without resorting to a mathmatical formula. So I dug through my collection of historical computing equipment and found, in the HP-67 manual, a formula and a few hints.
The Gregorian calendar that we now use was started by Pope Gregory XIII in 1582, and it was used to adjust the original Julian calendar, which was, by then, 10 days out of sync with the seasons. The Gregorian calander adjusted the months to be the same as the Julian calander was in 325 A.D. In short it restored the Vernal Equinox to March 21st.
To keep the whole thing in line over the next 20,000 years the following adjustments must be allowed for,
A leap year every four years.
Only Century years exactly divisible by 400 are Leap Years, ie 1600 is, 1700 aint.
Years exactly divisible by 4000 are common and not Leap Years.
apart from that, the Gregorian and Julian Calendars are the same, got it ? Good, so far!
To make things easier when it comes to working out the number of days between events or dates, a fellow named Joseph Justus Scaliger devised the Julian period and named it after his father, Julius Ceasar Scaliger. This system numbered each day from lunchtime on the 1st of January, 4713 B.C. From the use of the Julian Date we can find the period, in days between any date in history. The base for the period is 7980 years which takes into account, Lunar or Metonic cycles, Solar cycles and the cycle of induction, which was originally a schedule of periodic taxes or government requisitions in ancient Rome, the Epoch of these being in about 4713 B.C. See it all makes sense.
Countries moved to the Gregorian Calendar at various times,
Proclaimed in 1582
Adopted within a year by the Italian states, Portugal, Spain and the German Catholic states.
Protestant German states, 1699
England and it's colonies, 1752
Sweden, 1753
Japan, 1873
China, 1912
Soviet Union, 1918
and Greece, 1923.
So by giving you the Julian number for any one day you can also work out which day of the week it falls on, or you can compare dates in history, not to mention it's use in Astronomy.
N.B. The Julian Day number applies from NOON Greenwich Mean Time.
The Encyclopedia Britannica says so … also thanks to whoever wrote the Calendar Functions program for the HP-67 calculator, it's still a joy to use.
Provided that all has gone to plan,
This application prints three Page formats, a Month, a Day or a Year, this is based on the given date. To print a series of days, use the Range option in the Print Dialog box to choose the Days to print, or use the Range option to print a series of Months. The Year format always uses 9pt characters and can only print a single page. The 'Print This…' menu item is a short cut method of printing the current screen, as any options will be ignored. ( The printer may be s l o w while printing the 'Year to a page' format ). This application takes advantage of international resources and should use the host computer's Day and Month Names, and Abbreviation formats.
This application is shareware, that is, if you end up using it for any more than a few days then register yourself with me, by send the fee. You will be able to receive Free updates on request, of this and all other sandcastle Software items.
$30 for 3 disks of original sandcastles Shareware.
mail one of 'The following' to
Paul B Jones
P.O.Box 208
Moora 6510
Western Australia.
The following = Money !, or new disks, local currency, cheques, old computers,old Digital watches, old calculators, old computer books or manuals, CP/M software and manuals, Chocolates, lollies, original Mac software to the value of …
You'll get the idea …
regards, Paul B Jones
P.S. if you have paid fees to me, then send an original sandcastles disk and you'll get a complete upgrade for $5. (covers Postage anywhere, 3 disks, mostly better, some colour etc,(local notes, coins or stamps will be OK))
