Trammel is the bigger of the two moons. In the gate systems of Ultima III and Ultima IV, it is the phase of this moon that determines the gate that is currently open. In later Ultima installments beginning with Ultima V, Trammel is the moon whose phase is the destination gate for the first half of the night, until both moons are at equal hight on the sky.
Felucca is the smaller of the two moons. In the gate systems of Ultima III and Ultima IV, it is the phase of this moon that determines the gate that is the destination. In later installments beginning with Ultima V, Felucca is the moon whose phase is the destination gate for the second half of the night, as soon as both moons are no longer at equal height in the sky.
The moons played a part in the story of Ultima IX, where they were slowly pulled out of their orbits by the columns and threatened to collide and smash into Britannia, which would have meant the end of all life on the planet. Already their cycles were disturbed and made moongate travel totally impossible the normal way. The disaster was prevented at the last moment.
It is interesting to note that the phases of Trammel and Felucca are the exact opposite of Earth's moon; while our moon's orbit is counter-clockwise, Trammel and Felucca both orbit Britannia in a clockwise orbit (also seen on the Orrery). Therefore while on Earth, a crecent waxing moon starts on the right side, it starts on the left side in Britannia.
Appearance in the games
In Ultima III, they are only represented with numbers, and in Ultima IV and Ultima V with small moon phase icons. Their first detailed in-game appearance comes in the introduction sequence of Ultima VI, during the gargoyles' attempted sacrifice of the Avatar; curiously, their phases in this scene appear as if rotated 90 degrees. During gameplay, the moon phase icons return. In Ultima VII, Trammel and Felucca are only visually represented by their models mounted upon Moonglow's Orrery.
In Ultima IX, the moons are shown in-game and in a cutscene; however, there are differences between these appearances. While in the cutscene Trammel and Felucca are both white, in-game Trammel has a reddish hue. Of note is that they can also be seen in a cutscene that was ultimately dropped from the game, showing them low in the sky over the area surrounding the Shrine of Justice.
Reconstructed Trammel and Felucca from Ultima IX cutscene (thanks to Digital Lycaeum)
Cycles during the Month
The cycles of the moon during the month are as follows:
|“|| Under the auspices of Lord British, studies of the properties of the Moon gates are beginning to yield a clearer understanding of the Gates' mystical workings. People forecast that future citizens will use these gates as a normal means of distant travel. The destinations of the gates appear to be rigidly bound to the phases of the twin moons Trammel and Felucca. The appearance and disappearance of the gates are represented on most maps of the realm as phases of the moons. The gate active is indicated by the phase of the moon Trammel. Once a gate is entered, thy destination is indicated by the phase of the moon Felucca.|
|“|| In the heaven beyond our skies, dwell stars whose numbers are beyond our reckoning. Within our heaven, circling our world, sweeps our bright sun. Ten other orbs trace tight paths around our world. The twin moons Trammel and Felucca are desolate, their light only a reflection of the sun's brilliance.|
|“|| There exists an extraordinary cosmic association between the gravity of the moons and the delicate fabric of time and space. As though pulling the strings of some cosmic marionette, the moons cause radiant moongates to appear on the land below.|
|“|| As our twin moons, Trammel and Felucca, orbit our planet in their perfect, unchanging orbits, scientists speculate as to what might happen should there be a gravitational shift caused by any number of cataclysmic events. The gravitational pull would surely be altered, making their orbits extremely unstable. Should this unthinkable event happen, the moons might actually collide with the planet, causing a massive ecological disaster like none we have seen in our time.|