The highlight of the collection is the Patek Philippe Ref 5001T Sky Moon Tourbillon, the only known example of the watch in titanium. It could bring in $1 million to $1.5 million, Forbes reported.
The watch has 12 complications, including perpetual calendar, retrograde date, sky chart, moon phases, orbit display, sidereal time and minute repeating on cathedral gongs. It was made in 2002.
The five watches came from a previously unknown private collection of 12 watches.
The other four watches to go to auction are the Ref 5033T estimated to fetch $400,000 to $600,000; the Ref 5102T Celestial estimated $200,000 to $300,000; the Patek Philippe 1923 Officier estimated at $800,000 to $1.2 million; and the Ref 5103P estimated at $500,000 to $700,000.