The Cassiopeia is a time machine in the shape of a pocket watch. Given to Negi during the Mahora Festival by his student Chao Lingshen.
A series of time machines developed by Chao, born from a mix of technology and magic, they are all prototypes due to the fact that time skip is not yet a fully established technology, even in the future.
Performing a time leap requires the mana of the World Tree, and thus can only be used during the period of the Mahora Festival. In addition, the amount of time which can be traveled is limited by the mage, the amount of mana expended depends on the amount of time traveled, and one mage can only carry enough mana for a 24-hour jump, thus precluding multiple long jumps. However, a single time leap can carry any number of travelers provided they are all physically connected to the mage. In addition, special equipment and precise calculations are needed for a proper exit point, as a particularly “long” jump could transport the user inside the Earth or into outer space due to the spatial coordinates being out-of-sync.
The Cassiopeia can grant the user the abilities of absolute evasion and pseudo-time suspension. By using time leaps, the user can move to a different time, then return to his “original” time in a different location, thus allowing the user to avoid an attack even after being hit (including time leap attacks). Also, by repeatedly performing high speed time leaps to the same space, it is possible to imitate a suspension of time. In order to achieve practical combat usage, precise calculations down to the nanosecond and
accurate predictions of events and phenomena post-jump are absolutely necessary; it took two years of extensive simulations by Hakase and Chao to implement practical use and many restrictions still exist.