Everybody has that favorite calendar. You know, the one that makes you sad when the year is over; the one you may put somewhere discrete for the following year, just to look at the pictures one more time. It may be a favorite artist, or scenes from a place you visited. It may represent a cause. (I receive ones from the Humane Society, Cat Adoption Team, and Best Friends Animal Sanctuary annually.) It may be a calendar you made yourself, or one that was made for you by friends, children, or grandchildren. It may be something funny that always makes you laugh, no matter how bad your day is. Maybe it’s something really old and nostalgic that you just can’t throw away. Or maybe you just like saving money.
So if you’re like me, you have a drawer or shelf or box somewhere filled with these calendars. Imagine my delight when I found a way I could use them again and again!
It is called the Perpetual Calendar, which is a calendar that is valid for many different years. Perpetual calendars use algorithms to compute the day of the week for any given year, month, and day of month. With a Perpetual Calendar, you can figure out which years are the same, and use those old calendars again.
At the VP Calendar site, the 20th and 21st centuries are broken down into 14 different charts. Only 14, and that includes the conundrum that is Leap Year! I’m amazed, and I think you will be too.
Here’s how it works. Say, you want to find out which calendars in that drawer/ shelf/ box you can use next year, 2017. According to the chart at ALL CALENDARS OF THE PAST AND THE FUTURE you have quite a choice. Here are the years past that have identical dates to 2017:
1606, 17, 23, 34, 45, 51, 62, 73, 79, 90
1702, 13, 19, 30, 41, 47, 58, 69, 75, 86, 97
1809, 15, 26, 37, 43, 54, 65, 71, 82, 93, 99
1905, 11, 22, 33, 39, 50, 61, 67, 78, 89, 95
Now you know what to do with that 1623 calendar your ancestors brought over on the Mayflower.
I am the biggest pack rat, but even I don’t have calendars that go back anywhere near that far. There are still lots of choices from the last half century though. Most years have between 4 and 6 choices since 1966. Leap years have the least number; usually only 2.
So don’t throw away that Star Trek/ Firefly/ Lord of the Rings/ Gnomes calendar – save it and use it again!
Here are a couple of sites for you to start with:
VPCalendar.net : 20th & 21st Centuries
ALL CALENDARS OF THE PAST AND THE FUTURE: 1582 through 11582