Vintage Zodiac Aerospace GMT

In the 1960s, Zodiac introduced the Aerospace GMT with a design based in the previously issued Zodiac Sea Wolf. The first Zodiac Aerospace GMT (752-925) is believed to have been produced in 1962, it featured a chrome plated bezel which had a green triangle at the 24 hour mark. The dial was available in two colors: white or black. The second hand was thin with no lume. The 24 hour indicator consisted of a lumed arrow, whereas the hour and minutes where batons with some lume at their tip. The Aerospace GMT featured a bi-directional 24 hour bezel. At that time, this model was advertised with the slogan "Twice as much time for your money" due to the fact that this watch featured an extra 24 hour hand to track a second time zone. The 24-hour hand of this model could not be set independently, and it was making a full round per 24 hour. Having both hands geared together meant that the GMT offset was set by the rotating bezel.

Ref: 752-925
Diameter: 35.00 mm
Thickness: 11.00 mm
Lug width: 18.00 mm
Caliber: Zodiac Caliber 75

One of the first editions of the Zodiac Aerospace GMT 752-925 (1962) white dial, arrow-shaped 24 hour hand, cal 75. Found on eBay

The movement in Zodiac Aerospace GMT is an automatic caliber 75 (21 jewels), based on the caliber 70-72. The cal 70-72 (17 jewels) was an automatic movement featuring a date complication and was used in the Sea Wolf Datographic (ref 722-916). A few years later, the automatic GMT movements 75B and 76 were introduced, providing a quickest date function. The case of later models provided 20 ATM of water resistance. The diameter without crown was 35mm, with a thickness of 11mm. With those dimensions, Zodiac demonstrated that producing waterproof and relatively thin watches was possible! It was retailing at a price of $110 dollar at the time. The Aerospace model was also named the Aeronaut for a while, it had the same 752-925 reference. It was also available with a black or white dials. A model called the Aerospace Jet 758 was also produced, it used the same hands as the 752.

Ref: 752-934
Diameter: 35.00 mm
Thickness: 11.00 mm
Lug width: 18.00 mm
Caliber: Zodiac Caliber 75, 75B, 76

Second edition of Zodiac Aerospace GMT 752-925 (1966), red rectangular 24 hour hand, no lollipop second hand, platined bezel, white dial, cal 75. Search on eBay

Around 1965, a second edition of the 752-925 was produced. The dial featured more elongated lume inserts and the 24 hour hand was red with a luminescent tip. The 6, 9 and 12 hour markers were fluted. Some models have a patinated bezel instead of a polished one. The 20ATM models have the Aerospace script beneath the Zodiac logo, and the caseback is marked with 20ATM. The Aerospace GMT model 752-925 was available with a bicolor bezel.

Zodiac Aerospace GMT 752-934, Pepsi bakelite bezel. Credits: eBay listings

A third edition of the 752-925 model was produced later, featuring a distinctive rectangular lollipop hand. The hour markers on this third version are wider. One of the models of this edition was even available with a 10k solid gold bezel. It was once again available with a black or white dial. From 1968, new models with a bakelite 24 hour bezel were used, the reference for those models is different (finally!): 752-934 and -934B.