Tell me more about this watch. I am unclear about the outer two sets of markings. Why the pi?
It's a slide rule - effectively a mechanical analog computer. From the days before scientific calculators, laptops and iPhones. Found on Breitling Navitimer, Gallet Excel-O-Graph and Heuer Calculator amongst others. Used by pilots (as an example) to calculate fuel required, used and remaining, amongst other critical, complicated calculations.
Ever since I put this watch on the 1171 I’ve developed a whole new love for it. Pretty much wore it strait for the last week. Should’ve done this years ago.
Grandfathers watch, retirement gift given for 38 years as Manager of Hawkesbury Agriculture college in NSW.
Worn daily on his farm from new until the 90s