1) Once you have downloaded your times from http://websurf.hmnao.com/ , remember to find times for your Post Code/area/location for astronomical twilight (18 degrees).

2) You now need to copy the times using the function copy as table (only possible with Adobe Acrobat) and then paste the times into Excel. If you don't have Acrobat, copy normally and then using Excel convert text into columns. You must ensure at this stage that the copying has not resulted in any additional spaces. For example if there is a space after or before a time you must remove it. However, do not remove the spaces between digits. For example if there is an additional space in a cell before of after 12 30 delete the spaces. Do not delete the space between the numbers.

3) Now using the replace function, replace the spaces with a : This will convert all the numbers into times.

4) Calculating 1/7th for 'Isha time

=(today's sunset time+(1-today's sunset time + the next day's sunrise time)/7)

5) Calculating 1/7th for Fajr

=Today's sunrise-(1-previous day's sunset time+today's sunrise time)/7

6) Deducting four minutes from sunrise time
=sum(sunrise time)-time(0,4,0)

7) Adding four minutes to sunset time for Maghrib.
=sum(sunset time) + time(0,4,0)

Use steps 6 and 7 for Zawal too except change 4 (minutes) for 5.