to French law at the time requiring visible hall marks on all gold. The 1511 Marine Chronometer was famously owned by Oceanographer Jacques Cousteau and when introduced in 1974 had a list price of £761, by contrast the Moonwatch was on the market at £124.50 and the now coveted Omega Bullhead was only £114.50. Calibre 1510: A non Marine Chronometer designated watch with an accuracy of 1 second per month branded as the Constellation Megaquartz. The watch came in a very similar case to the Marine Chronometer but without the plaque and 14K bezel, available in Stainless Steel or 18 carat gold. The Calibre 1510 was most famously produced with an aventurine crystal dial, nicknamed the ‘Stardust’. The watch came in a number of variations of dials: stardust (silver and gold), waffle dial in black, blue and brown and electric blue dial; the rarest of these variations is the blue waffle dial The total production run of calibre 1510 was also 1000 units, around 800 of which were produced in stainless steel with a variety of dials and 200 were produced in solid 18 carat gold with either stardust, solid 18 carat or electric blue dials. The original list price in 1974 for a calibre 1510 was £604 in stainless steel and £3275 in 18 carat gold. The movement in both the 1510 and 1511 is fundamentally identical and all parts can be interchanged, the only difference in the two movements is the designation on the movement plate of either 1511 or 1510. It is rumored that the caliber 1510 was also sent to Besançon for certification, however despite being tested and performing to the same level as the Marine Chronometer was never certified. A number of the remaining calibre 1510 watches had individual numbers engraved on the case back, this was to allow their identification during testing. It is most likely that this was a marketing decision by Omega so as not to degrade the marketability of the Marine Chronometer, for which Omega charged a £157 premium at the time (which was the same price as a brand new Omega Flightmaster on bracelet). Further developments In 1976 Omega refined the design of the Marine Chronometer and the Constellation (previous known as Calibre 1510) with the introduction of the caliber 1516 Marine Chronometer and the documented introduction of the calibre 1515 in Constellation models. Although widely documented, the caliber 1515