OMEGA First OMEGA in Space 310.30.40.50.06.001: specs and checks

Sapphire, shaped like plastic

The crystal specification on this reference is one of the more consequential sentences OMEGA publishes anywhere in its range:

Hesalite-like form, scratch-resistant sapphire crystal with anti-reflective treatment inside.

Read it slowly. The form is hesalite — the tall, domed profile of the acrylic crystal that Speedmaster buyers associate with the traditional Moonwatch. The material is sapphire.

That combination inverts two habits at once.

It will not polish. Hesalite is acrylic: scuffs and light scratches come out with a plastic polishing compound in a few minutes, which is a large part of why people like it. Sapphire does not. Attempting the same treatment achieves nothing and risks the case.

It will chip. Acrylic absorbs a knock and deforms. Sapphire is hard and brittle: it resists everything until it does not, and then it loses a bright flake. On a domed profile that flake is usually on the curve or at the turn-down, where it is nearly invisible looking straight down.

So inspect it as sapphire, not as hesalite: tip the watch, rake a light across the dome, and travel the full circumference.

And when you sell it, say what it is. A buyer who thinks they have bought a polishable acrylic crystal will be unhappy twice — once when it will not polish, and once when they discover why.

Fifty hours, hand-wound

The movement is the calibre 3861: manual-winding, 50 hours, Master Chronometer certified.

Fifty hours is the shortest reserve OMEGA publishes among the references here, shared with the Hesalite Moonwatch, which runs the same 3861. Every 89xx movement here carries sixty, and the '57's manual 9906 carries sixty as well.

Combine a short reserve with manual winding and the ownership is specific: this watch needs attention most mornings. A day skipped is a watch stopped and a time to reset. Some buyers want exactly that and some do not, and it is much better discovered in your description than in their first week.

The winding itself is your best diagnostic. Take it from stopped, feel the tension build evenly, and note where it ends — then stop there. There is no rotor and no slipping bridle standing between an enthusiastic owner and a broken mainspring.

Small case, long reach

39.7 mm in diameter, 48.00 mm lug to lug, 13.38 mm thick, 133 g.

The diameter suggests a compact watch; the lug-to-lug says otherwise. Eight and a third millimetres of overhang is substantial, and it is what determines whether the case sits flat on a given wrist.

Lug width is 19 mm — stocked but not common, and a buyer will assume twenty.

The rest of the sheet

Water resistance 5 bar (50 metres / 165 feet), the same as every other Speedmaster documented here and the same warning: rain and hand washing, nothing further.

The dial is listed as blue ‑ grey, which is the kind of two-word colour that photographs as one or the other depending on your light. Shoot it with a fixed white balance and look at the result before you publish it.

The clasp is a foldover butterfly with comfort setting: hidden, load-bearing, and carrying a micro-adjustment that should click into each position and stay there.