Omega

Manual winding with caliber 1861,solid case back with hesalite crystal or caliber 1863 with sapphire crystal and exhibition caseback? All input is most welcomed.

If you care more for it being NASA-flight qualified (and robustness that comes with that) and ‘as close to the original as possible’ then go for the 1861 If you like staring at complex movements (and this happens to be one of the prettiest) and want the c... 

It's a beautiful movement to look at.

1863

quite a value

First Omega In Space

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. . . the highlights of both versions: ref 3572.50 with hesalite crystal and sapphire back showcasing a cal 1863 movement. [Andrew's ref 3572.50, 2013] Our Andrew had one, as did at least one other member of this community. They're not overly difficult to...