Skip to content

Random Connections

A collection of photography and exploration focusing on Upstate South Carolina and beyond.

  • Home
  • About Us
  • Photos
  • Resources
  • Other Voices
  • Post Archives
  • Home
  • Religion
  • Paschal Moon

Paschal Moon

Posted on March 30, 2010 By Tom No Comments on Paschal Moon
Religion, Science

Passover Moon

Last night was the first night of Passover. According to Wikipedia…

Passover begins on the 15th day of the month of Nisan, which corresponds to the full moon of Nisan, the first month of the Hebrew calendar, in accordance with the Hebrew Bible.

This is also the first full moon after the vernal equinox, and Easter is always the first Sunday after the first full moon after the equinox. Easter, Ash Wednesday, Palm Sunday, and Pentecost are the original “moveable feasts,” so-called because the dates are variable. However, all are calculated from the Paschal Moon.

So, let’s say you don’t have a calendar handy, but need to know the date of Easter for some random year. There are are some algorithms you could use. If you have your copy of “Practical Astronomy with your Calculator” by Peter Duffett-Smith you could use that. Duffett-Smith used an algorithm by Samuel Butcher published in Nature in 1876 (Nature, 1876 April 20, vol. 13, p. 487.) It was described by M. J. Montes as follows:

This algorithm holds for any year in the Gregorian Calendar, which (of course) means years including and after 1583.

In the text below, / represents an integer division neglecting the remainder, while % is division keeping only the remainder. So 30/7=4 , and 30%7=2 .
a=year%19
b=year/100
c=year%100
d=b/4
e=b%4
f=(b+8)/25
g=(b-f+1)/3
h=(19*a+b-d-g+15)%30
i=c/4
k=c%4
l=(32+2*e+2*i-h-k)%7
m=(a+11*h+22*l)/451
Easter Month =(h+l-7*m+114)/31 [3=March, 4=April]
p=(h+l-7*m+114)%31
Easter Date=p+1 (date in Easter Month)

The algorithm uses a series of successive divisions to reach the answer. In case you don’t have your calculator handy, but do have online access, I’ve created a Google Docs spreadsheet that does the calculation for you. All you have to do is enter the year in question. Of course, you could just use this handy form, or refer to this chart.
Practical Astronomy

Tags: Astronomy Easter Science

Post navigation

❮ Previous Post: Greenville, NORTH Carolina
Next Post: Children’s Cemetery Oddities ❯

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Categories

  • EdTech (200)
  • Entertainment (201)
  • Family (119)
  • Gear (115)
  • General Technology (99)
  • Geocaching and Maps (208)
  • History and Genealogy (256)
  • Internet (144)
  • Local (447)
  • Miscellaneous (540)
  • Music (189)
  • Paddling (240)
  • Photography (778)
  • Podcast (6)
  • Rambling (223)
  • Rants (160)
  • Recipes (34)
  • Religion (48)
  • Restaurants (165)
  • Science (48)
  • Things Overheard (29)
  • Travel (410)
  • Uncategorized (129)
  • Washington Sabbatical (113)
  • Weirdness (59)

Recent Posts

  • Musical Hoarding
  • In Search of Cambridge Hash
  • Ancestral Ages
  • Orphaned Graveyards and Family Connections in Ninety Six
  • Paddling Cedar Creek through Congaree Swamp

Recent Comments

  • Tom on From Buzzards Roost to Chappells
  • Gary (AKA Sought and Found) on From Buzzards Roost to Chappells
  • Nathaniel Emerson on Where Did the Swamp Rabbit Go?
  • Steuart Brice on Exploring Southern Fairfield County – Part 1, Old Lebanon Church
  • Jeni Bowers on Remembering Merrittsville

Tags

blogging cemetery Christmas Columbia Edisto River edtech Entertainment family Flickr Florida Furman Furman University gear geotagging Ghost Town Ghost Towns Google Earth Google Maps GPS Greenville Greenville Chorale hiking history Instructional Technology kayaking Lake Jocassee LCU Lowcountry Unfiltered maps Music North Carolina Paddling Photography rambling restaurant Restaurants review singing social networking South Carolina time-lapse Travel video Washington Washington State
April 2021
S M T W T F S
 123
45678910
11121314151617
18192021222324
252627282930  
« Mar    

Copyright © 2021 Random Connections.

Theme: Oceanly by ScriptsTown