Luchazi lunar calendar

Traditionally the Luchazi people have a lunar calendar with thirteen lunar months, each of 28 days. They give each month a name as the moon appeared known as kutentama ca ngonde in the western sky, after sunset. The Luchazi new year begin in April when the harvest is ready.

Converting the Gregorian year to lunar calendar year

The world primarily uses the Gregorian calendar which is the international standard for civil, business, and administrative purposes. Introduced in 1582 by Pope Gregory XIII, it is a solar calendar with 12 months, 365 days, and a leap year every four years (with specific century rules). The question is: how do we convert it to lunar calendar? We want to convert a Gregorian date to a calendar year in a hypothetical lunar calendar step by step:

Step 1: Understand the calendar structure

We have a lunar calendar with:

• 13 lunar months in a year
• Each lunar month = 28 days

So the length of 1 year in this calendar is:

13 × 28 = 364 days

Step 2: Compare with the Gregorian year

A Gregorian (solar) year has about 365.2425 days (accounting for leap years).

The difference per year:

365.2425 - 364 = 1.2425 days.

That means each year in this lunar calendar is shorter than the Gregorian year by 1.2425 days.

Step 3: Accumulated difference over years

This difference means dates will drift relative to the Gregorian calendar.

If we fix a reference point where they align, then after N years, the difference grows to N × 1.2425 days. When the drift reaches about 365.2425 days, the lunar year would have gone through a full cycle relative to the Gregorian year.

But here, the question seems to be asking: “If today is Gregorian year T (some reference), what year number would it be in this lunar calendar counting from some fixed starting point?”

Let’s choose: Suppose in year 1 of the lunar calendar, it was also Gregorian year 1 AD (just as a convenient anchor).

Step 4: How many lunar years have passed in Gregorian year 2026?

From year 1 AD to 2026 AD is 2025 full Gregorian years (because year 1 to year 2 is one year elapsed, etc.).

Let L = number of lunar years completed by the start of Gregorian year 2026.

At the start of Gregorian year 1 AD, lunar year 1 started.

At the start of Gregorian year 2 AD, the lunar calendar has advanced 1.2425 days more than a full year of its own? Wait, careful:

Actually, easier:

Let’s count in days from the start of year 1 AD to the start of Gregorian year 2026.

From 1 Jan 0001 to 1 Jan 2026 = 2025 Gregorian years.

Total days elapsed (accounting for leap years):

Leap years from 1 AD to 2025 AD inclusive = How many?

Step 5: Leap year count

Leap years: every 4 years except centuries not divisible by 400.

Years 1–2025:

Count multiples of 4: [2025/4] = 506 

Centuries: 100, 200, …, 2000.

Centuries divisible by 400 in that range: 400, 800, 1200, 1600, 2000 → 5 centuries.

So leap years = 506 - (# centuries not divisible by 400).

Centuries in 1–2025: 100,200,…,2000 → 20 centuries.

Not divisible by 400: 20 - 5 = 15.

So leap years = 506 - 15 = 491.

Step 6: Total days from 1 Jan 1 AD to 1 Jan 2026

Days = 2025 × 365 + 491.

2025 × 365 = 739, 125

739, 125 + 491 = 739, 616 days

Step 7: Convert to lunar years

Each lunar year = 364 days.

Number of full lunar years elapsed:

739,616 ÷ 364

364  × 2000 = 728,000

739,616 - 728,000 = 11,616

364 × 31 = 11,284 (remainder 332)

So 2000 + 31 = 2031 full lunar years have passed from start of lunar year 1 to start of Gregorian year 2026.

Step 8: Determine current lunar year

At the start of Gregorian year 2026, we are in lunar year 2032 (since 2031 years completed means we’ve started year 2032).

Step 9: But check if we need to adjust for start-of-year definition

Gregorian year 2026 started at day 739,616 of the era.

Days into lunar year 2032:

739,616 - (2031 × 364) = 332 days into lunar year 2032.

So in Gregorian terms, Jan 1, 2026 = day 332 of lunar year 2032.

That means from the Gregorian date, the lunar year number is 2032

So if we align year 1 lunar with year 1 Gregorian (1 AD), then Gregorian year 2026 = Lunar year 2032 (most of it, anyway).

Another simple example: say in 2025, given the problem doesn’t give epoch, a common trick:

13 months × 28 days = 364 days, which is about 1 day short of solar year. This means after many years, the new year lags.

But without offset specified, maybe they expect:

In year 2025 Gregorian, if this lunar calendar started in 1 AD, then

2025 × 365.2422 ≈ 739,000 days

739,000 ÷ 364 ≈ 2030 lunar years

So the lunar year would be 2030 in 2025. In 2026, the lunar year is 2032.

Please feel free to advise if you have another answer and method of converting.

Months of the calendar in Luchazi

Today the Luchazi people have adopted the system of twelve months, and the names of the months are based on the climatic conditions, vegetation conditions and temperature cycle of the year. Therefore, the names of months may vary from one region to another because of different climatic conditions (for example Angola has two climatic seasons and Zambia has three seasons). These months in Luchazi are:

1. April = Ku-uana.
2. May =Kuhu or kusamba.
3. June = Kavavu.
4. July = Konda mema.
5. August = Katuinye.
6. September = Kantsukue.
7. October = Kantondue - Kuenye.
8. November = Kulombo.
9. December = Kazimbi.
10. January = Ndzimbi.
11. February = Kuvozi.
12. March = Kutatu.

Here are some months in other Ngangela languages that differ from Luchazi:

1. August = kalyandengo.
2. September = ntumbakatwinye.
3. November = hala.
4. Other Luchazi people add Kambamba na Lisa for April.