Generate date sequences

jhanarato commented 1 year ago

Use the configuration in issue #3 to generate the dates:

In a normal season there are 4 lunar cycles of waning, new, waxing and full.
New & full moons are the uposatha and wan prah.
Waxing and waning are wan prah only.
In a normal season there are 8 uposathas separated by 15 days except the 3rd and 7th which are 14 days after the previous uposatha.
In some years the hot season is extended by another lunar cycle. The two extra uposathas are separated by 15 days.
In the icalendar file it seems that the waxing & waning wan prah days fall on the 8th day after the previous uposatha regardless of whether the duration between uposathas is 14 or 15 days.
We need to handle any arbitrary adjustments. Allow a moon day to occur a day before or after the expected date. It seems unlikely that any adjustment would be greater than 1 day.

jhanarato commented 1 year ago

The output of my adjustment finding script:

Gimha season 2016: [15, 15, 14, 15, 15, 15, 15, 15]
Gimha season 2020: [15, 15, 14, 15, 15, 15, 15, 15]
Gimha season 2025: [15, 15, 14, 15, 15, 15, 15, 15]
Gimha season 2030: [15, 15, 14, 15, 15, 15, 15, 15]

So for our icalendar file there are four adjustments. In each case the seventh uposatha of the hot season has changed from 14 days to 15 days.

jhanarato commented 1 year ago

Sequences for half moons:

Normal      [8, 15, 15, 14, 15, 15, 15, 14]
Extra day   [8, 15, 15, 14, 15, 15, 15, 15]
Extra month [8, 15, 15, 14, 15, 15, 15, 14, 15, 15]

jhanarato commented 1 year ago

Sequences for full moons:

Normal      [15, 15, 14, 15, 15, 15, 14, 15]
Extra day   [15, 15, 14, 15, 15, 15, 15, 15]
Extra month [15, 15, 14, 15, 15, 15, 14, 15, 15, 15]

jhanarato commented 1 year ago

Sequences work. Now working on sequence -> date conversion.

jhanarato commented 1 year ago

All good. We can see all the seasons with dates from 2010 to 2030 as expected.

jhanarato / uposatha

Generate date sequences #4