Here some details about this watch and his evolution from last '50:
1958-61 - Cal.19AS and 29AS, ref.7042-1/2/3/4, matt Radium dial with full lume hours hand, diamond ring index, printed "SWISS". Low crowns, 100mt. water-proof.
1961-62 - Cal.290 ref. 7150-1 , Radium dial with full lume hours hand, glossy dial with electroplating gold graphics, printed "SWISS MADE". Low crows and from now 200mt. water-proof.
1962-64 - Cal.290 ref. 7150-2/3, Tritium dial with luminescent rumbling hours hand,
thick crowns, matt or glossy galvanic dial, gold graphics and from now printed "T SWISS MADE T" (Tritium).
1964-65 - Cal.290 ref. 7494-1/2, Tritium luminescent dial and hands, rhomboid hours hand, thick crowns, matt or glossy galvanic dial with gold graphics.
1965-69 - Cal.290 ref. 7594-1/2/3, Tritium luminescent dial and hands, rhomboid hours hand, thick crowns, matt or glossy galvanic dial with gold graphics.
Longines Calibre 19AS automatic without inverters,
18.000 alternations / hour and indirect center seconds, diameter 25.3 mm. and height 6 mm. The charging movement was devoid of inverters but with a train of ratchets, probably a patent of the same Longines, which allowed the charging of the barrel in both directions of rotation of the winding rotor.
New automatic movement cal. 290 with inverters. slightly larger diameter and different rotor shape. Produced from 1958,
19800 alternations / hour, automatic center seconds, this time direct, 26mm diameter., Height 6 mm.
From what I could remember the reference numbers it was to indicate the type of case.
Max
Advert from '50
![[IMG]](https://omegaforums.net/data/attachments/283/283840-c448c69bbc75dc6e48f2308532513833.jpg)
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