Some specifications for this reference are on file; the record is incomplete.
Arnold & Son · Perpetual Moon
Perpetual Moon
Ref. Perpetual Moon
Missing informationCore fields not yet documented for this reference: Case diameter, Caliber, Production, Water resistance, Dial
Authentication Notes
Dial
A large moonphase disc shows its own quality
The disc dominates the dial, which means its finish, the crispness of the moon's edge and the depth of the sky field are all displayed at a size where flaws are obvious. Printing or plating defects that would be invisible on a conventional aperture-sized moonphase are plainly visible here.
Movement
Moonphase precision is a gearing claim and gearing is countable
A standard moonphase uses a 59-tooth wheel and drifts about a day every two and a half years. A high-precision one uses a much larger tooth count to approximate the synodic month more closely, and the accuracy claimed follows arithmetically from that count. It is one of the few specification claims in this catalog that can in principle be verified by counting teeth through a display back — laborious, and conclusive.
Inspection points
No inspection checklist has been published for this reference.