The CK2915 has multiple versions (you will find a -1, -2, or -3 added to the reference number) that could be considered more or less as small updates if you want. If you are looking for a CK2915, expect to pay a fortune (50K Euro and up). More important: try to find an original one that has not been tampered with. There is so much money going on in these very first models, that it also attracted crooks that are after your money. In a bad way. Newly made cases, movements from other watches, refitted bezels from a later period and so on. Be very cautious in any case.
The CK2915 houses the Omega caliber 321 movement, with a column wheel chronograph. This Lemania (caliber 2310) based movement went out of production in 1968 when Omega introduced the Speedmaster Professional 145.022.The very first Speedmaster as Omega introduced in 1957. Together with the Seamaster 300 (CK2913) and Railmaster (CK2914) this model had a sporty look with its curved lugs, black dial and broad arrow hands. Initially meant to be a sports chronograph, using the dashboard clocks of Italian sports cars of that time as an inspiration.
Although not all of these Speedmaster models in this section are considered a ‘Moonwatch’ – as they were introduced way before NASA chose Omega to become the official timepiece for their astronauts – I will still use this category for them in this Speedmaster buyer’s guide. These early models are considered to be the ancestor of the Moonwatch.