The Harvest, the Planting, and the Shining

The Harvest

Once every 308 days, The Two Moons of M'Brell, The Traveler eclipses the Dark Lady. This event is known in Western Nehwon as The Harvest. While different cultures celebrate the Harvest differently, all recognize this event as a time of assessing abundance.

• In Lankhmar, the city celebrates The Harvest by having city-wide parties during the entire week that The Harvest occurs. The King of Lankmar sponsors dozens of events around the city, including various entertainment venues, Bier und Schwein Booths, and prize winning contests.
  

  Hungry Man by Chad Watson via Midjourney
  

  A Buffet by Chad Watson via Midjourney
  
  To launch the festivities, the King of Lankhmar goes on a wild boar hunt, where he and his hunting party often return with scores of giant wild boar, most of which are distributed amondst the Bier und Schwein Booths.
  

  Boar Platter by Chad Watson via Midjourney
  
  Additionally, since the official animal of Lankmaria is the bear, one of the contests sponsored by the King of Lankhmar is to award an individual or party a grand prize for bringing back an unharmed and living male bear; the largest bear wins. After the festivities, the largest bear is added to the King's personal collection of bears. The rest are returned to the wild where they were found by several different Druid Groves.

Lankhmarian Bear by Chad Watson via Midjourney

The Planting

Once every 61 months, The Traveler not only eclipses the Dark Lady, the planet M'Brell eclipses them from Sonne, resulting in a double lunar eclipse. This event is known as The Planting. It is said that any child conceived on this day shall be honored amonst the gods. As such, each culture in Western Nehwon celebrates fertility in various ways, which range from fertility rites to great plantings of seedlings throughout the forests.

• In the villages of the Great Forest, young men and women that have reached their age of maturity are encouraged , but not forced, to partipate in dancing and festivities that last for four days, followed by a "love-fest" that lasts for three days. A great number of children are sired during these events. All peoples of the Great Forest participate in their own way, regardless of age, fertility or sexual orientation.
  

  Fertility Rites by Chad Watson via Midjourney

The Shining

Once every 122 months, the two moons not only eclipse one another, they eclipse Sonne at the same time, resulting in a double solar eclipse. The Shining is recognized by many cultures as a period of time during which mortals can communicate with their gods. It is said that the gods manifest amongst their people, sometimes obviously and sometimes covertly, to bless those who honor them in some way.

• One such event took place decades ago in the city of Mythan Belanore. An avatar of Corellon Larethian appeared in the city dressed as a humble sage. He walked from the center of the city to the gates of Candlekeep, whereupon he requested the audience of Little One, an ogre sage that spends most of his time alone in study. For a period of 11 sleepless days, Little One and Corellon produced 11 great tomes, one on each day.
  

  Little One by Chad Watson via Midjourney
  
  After completing the final tome, Corellon is said to have kissed the back of Little One's right hand and then on his forehead right between his eyes, disappearing right afterwards. Little One will not speak of this event, but has produced a great number of books since then.

Double Eclipse by Chad Watson via Midjourney

To determine how often the two moons would come into perfect alignment, we need to find the least common multiple (LCM) of their orbital periods. The orbital periods are 28 days for The Traveler and 77 days for The Dark Lady.
First, let's factorize the periods into their prime factors:
28 = 2^2 * 7 77 = 7 * 11 The LCM is found by taking the highest power of each prime number that appears in the factorizations:
The prime factors are 2, 7, and 11. The highest powers are 2^2, 7, and 11. So, the LCM is: 2 2 × 7 × 11 = 4 × 7 × 11 = 28 × 11 = 308 2 2 ×7×11=4×7×11=28×11=308
Therefore, the two moons will come into perfect alignment every 308 days.