Choghadiyos
All important works should be commenced during or favorable chaughadiyo.

There are seven types of chaughadiyos. Each day is divided into two time periods: daytime - the period from sunrise to sunset - and night-time - the period from sunset to sunrise. Each period contains eight Chaughadiyos. To calculate the duration of each Chaughadiyo, divide the respective time periods by eight. Thus, in each period any one of the seven different types of Chaughadiyos will occur twice.

The sequence of daytime and night-time Chaughadiyos varies for each day. However, for each day, the sequence is the same. That is, the sequence for Monday is different to that for Tuesday, which in turn is different to that for Wednesday, etc. But, the sequence for each Monday is the same, as it is for each Tuesday, etc.

Example
Day 1: Sunrise at 6:39 am
           Sunset at 6:25 pm
Day 2: Sunrise at 6:41 am

The daytime period is 11 hours and 46 minutes (706 minutes).
The night-time period is 12 hours and 16 minutes (736 minutes).
Therefore, each daytime Chaughadiyo lasts 706/8 = 88.25 minutes = 1 hour 28 minutes 15 seconds. 
And each night-time Chaughadiyo last 736/8 = 92 minutes = 1 hour 32 minutes.

Thus, to determine a good time to commence important works, check the time period between which such work can be initiated and select a favorable Chaughadiyo within that specified time period.