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# Lunar calendar

## what do you need?

1. A pen and a piece of paper
2. Knowlwdge related with calendars.

## Exercise.

Calculate the date of the photografs in Islamic calendar.

## Working out

##### What do we know?

We know the formula below, that shows a connection between Islamic calendar and Gregorian calendar:

We are given two dates, both in gregorian calendar but related with different lunar phases.

##### What do we have to find out?

The aim of this exercise is to learn how to calculate a date in Islamic calendar when we know a date of a lunar phase in Gragorian calendar.

##### Work out

1. We're going to calculate the dates of the photographs below:

cuarto creciente del 17/12/2008             cuarto menguante del 20/11/2008
2. Let's do the exercise with the date 17/12/2008. (Later, you can try doing the exercise with 20/11/2008)
3. First,Pasamos las fechas de 30 Marzo 1938 ,1 Enero 1388 a días y 17 Diciembre 2008 a días.
4. We named:

March to the number of days corresponding to March, 30th 1938 (Gregorian calendar)

January to the number of days corresponding to January, 1st 1388 (Islamic calendar)

December to the number of days corresponding to December, 17th 2008 (Gregorian calendar)

x to the number of days corresponding to December, 17th 2008 (Islamic calendar), que es lo que queremos hallar.

With all this, we have the formula below:

5. This formula above will help you to calculate x, wich is days corresponding to the data of December, 17th 2008 (17/12/2008)
6. To calculate the year corresponding to Islamic calendar, do:

. Ceiling(x) is the smallest integer not less than x, the solution, corresponding to the year in Islamic calendar.
7. When you get decimal numbers in the previous section, use this cross-multipication:

1 year → 354 (days in the Islamic calendar)

Decimals → y (days in the Islamic calendar.)

8. Once we have the day and the month (considered 0 in January in previous section), since we know the number of days of each month in Islamic calendar. Remember how to calculate the year in section 5.

lunar_calendar.txt · Última modificación: 24/04/2017 13:13 (editor externo)