Escapement
Technical info: Nikon D700, AFS 60/2.8 G Micro with 72mm of extension tubes. Watch inside diffuser box. Lit by three Nikon SB900s, triggered by the built-in flash on the D700 in commander mode.
Images are aways clickable for larger versions.
First thought: what on earth is it? The pallet fork and escape wheel of the Jaeger Le-Coultre Gyrotourbillon 1 perpetual calendar. The escapement sits within two rotating cages, which move in different axes to counter the effects of gravity. What you’re looking at is the unlocked escapement fork, now allowing the escape wheel to advance by one tooth and transmit its impulse to the oscillating balance. The pinkish synthetic ruby jewel (oblong object at center, in plane of focus) is about a millimeter in length.
One last thing – the watch in question does’t hack, so the cage is constantly in motion. Photographing this thing in the desired orientation is next to impossible because it never stops, can’t be stopped, and by design doesn’t cover the same orientation twice for several hours! MT
The full set and writeup is here on Fratellowatches.