Hello again,
Continuing the extension series for Lumi, this time I introduce the Vietnamese Lunar Calendar: lunar calendar right on Mac. Today's lunar date is already displayed in the menu bar, click ⌃⌥⌘L to open the entire lunar month in the top corner of the screen.

🎯 Why I built the Vietnamese Lunar Calendar

Many important days in the household are still calculated according to the lunar calendar: the first day of the month, the full moon, the lunar birthdays of parents. Every time I need to know what the lunar date is today, I have to pick up my phone to check the eternal calendar. Anniversaries fall on different solar dates each year, so I have to look them up every year.

✨ Main features

• Lunar date in the menu bar: next to the Lumi icon with the moon image and today's lunar date, for example 12/9, changes to a new date at midnight. Hover over it to see the day of the week, solar date, and year of the Heavenly Stem and Earthly Branch. Click to see how many days until Tet, open the calendar, copy today's lunar date, or change the date.
• Four types of calendars: The calendar page (default) like a tear-off calendar, a compact month next to it. A wall calendar with holiday names recorded right in the box. Hourly astrology with a circle of 12 time frames, and auspicious hours highlighted in gold. According to the moon, it divides the lunar month into early, middle, and late weeks, with a moon image for each day.
• Each day, by the moon: Each day shows the lunar date, marking the first and full moons. Select a date to view the Heavenly Stem and Earthly Branch, auspicious hours, and seasonal points.
• Pre-recorded holidays: New Year, New Year's Eve, Hung Kings' Commemoration Day, Buddha's Birthday, Vu Lan, Mid-Autumn Festival, God of Land and God of Kitchen Day, holiday and anniversary dates. Any that are unnecessary can be turned off in Settings.
• My days: save anniversary dates, lunar birthdays, and monthly worship dates. Each year the calendar calculates the solar dates automatically, marking them on the month and displaying them in the Upcoming section.
• Date conversion: convert solar dates to lunar and vice versa, including leap months, for every year from 1800 to 2199.
• Swipe with trackpad or keys: scrolling with the mouse or swiping the trackpad allows you to slide through the calendar with your hand across the months. Arrow keys navigate through the days, ⌥← and ⌥→ change months, T returns to today, ⌘C copies the selected date.
• Copy lunar date: three formats to choose from, complete "Wednesday, 21/10/2026, the 12th of September in the Year of the Horse", just the lunar date, or concisely "12/9 Year of the Horse".
• Interface: light, dark, or according to macOS, adjust the background transparency, week starts on Monday or Sunday. Press the Keep Open button to keep the calendar when you switch to another app.

🔐 Required extension permissions

• Clipboard, to copy the lunar date.
• Lumi's menu and a separate icon on the menu bar, to display today's lunar date and the number of days until Tet.
• Timer, once a day at midnight, to change the menu bar and the open calendar to the new date.
• Time zone, to know what date it is according to the Mac’s time.

The calendar does not connect to the internet; everything is calculated right on the device. My days are saved on the Mac.

👤 For whom

• People who frequently check lunar dates: first day of the month, full moon, going to the temple, lighting incense.
• People keeping track of family anniversaries and lunar birthdays.
• People who often look at auspicious hours and seasonal points.
• Vietnamese living abroad: today is calculated according to the machine's time zone, and the lunar date is still accurate according to the Vietnamese calendar.
• Those who work on Mac all day and do not want to pick up their phones just to check the date