How to Determine Easter With an Ephemeris

If you want to find out the date for Easter this year (or previous years), you don't need to wait for the latest calendar to come out or search the Internet for the information. Instead, you can calculate the date yourself with a handy ephemeris available for purchase online or at your local bookstore.

Instructions

Difficulty: Moderate

Find the First Day of Spring

1. Take out your ephemeris and familiarize yourself with how it is laid out. Skim through the pages of the book with all of the months of the years laid out in tables.
2. Turn to the front of the book and look at the phenomena explanations and the introduction. Locate the moon phase section as well as the symbols for the planets and the signs. Familiarize yourself with all the symbols.
3. Locate the month of March of the year you want to calculate the date for Easter. Find the column with the symbol for the sun. Note that the sun has the symbol for the sign of Pisces in its column in the beginning of the month.
4. Follow your finger down until the symbol of the sign under the sun changes to the symbol for Aries.
5. Note the day of the month this happens. It's the vernal equinox--or the first day of spring--and is the first piece of data you will need to calculate the date for Easter.

A Full Moon and a Sunday Away From Easter

6. Remember the symbol you saw in the front of the book under the moon phase section that denoted a full moon. It is a circle that is not filled in. The black filled-in circle represents the new moon, and the open circle denotes the full moon.
7. Go back to the page for March and look at April too. Locate the section, usually boxed in, for these two months for moon phases and eclipses. Look for the first full moon that occurs after the date of the spring equinox in March. This full moon may be in the latter part of March or the first part of April.
8. Now look at the dates and the days of March or April immediately following the full moon date you located to find out the date for Easter. You're looking for the Sunday that comes right after the full moon.
9. Place your finger on this first Sunday that comes after the first full moon occurring after the first day of spring, which was the day the Sun entered the sign of Aries. This is your approximate Easter Sunday date. There is just one more check you need to make.
10. Be aware that your ephemeris follows the time of Greenwich, London. Depending on where you live, adjust the data in the ephemeris for your time zone and daylight or standard time. (See the "Resource" section on this page for a handy international time zone chart.) Now you have the correct day and date for your Easter Sunday.