The inner circle shows the moon. A pointer indicates the age of the moon, between 1 and 30 days. The black and white disk above the centre shows the moon's phase. The white disk rotates once in a synodic month. The inscription around the moon phase indicator says "sphericus archetypum globus hic monstrat microcosmum", which translates as "This spherical globe here shows the archetypal microcosm". Howgrave-Graham suggests that the scribe erroneously put "microcosmum", when "macrocosmum" is the more obvious word. Opposite the moon circle is a weighted pivoted disc, containing a small painting of Phoebe, representing the moon. The inscription reads: "Sic peragrat Phobe", or "So progresses Phoebe".