Constellation Lume Identification / Hazard Assessment

Davidt

If I had to make a call, I’d say tritium as well.

• The colour looks like tritium more than radium.
• I still can’t recall a confirmed radium watch registering only 0.30.
• if it continues to glow faintly (I’m a dark room) after being hit with a bright light, that again suggests tritium.

padders

To the OP, do you know the serial? If it’s greater than ~20m that too indicates a high likelihood of tritium. The changeover was around there or just before.

Tritium lume emits only beta particles which is mostly attenuated by the crystal or in the open air a single sheet of paper. It is not much of a hazard vs radium which kicks out alpha and gamma radiation: different gravy.

Beta emitters are safe enough to give to idiot students to play with on a workshop the bench. Ask me now I know.

seekingseaquest

FWIW, I assume this is tritium, and I fully support your decision to research thoroughly and then make your own choices about your health. That’s what I did, and I made the decision to avoid radioactive watches altogether.

bgrisso

central retina better for detail and color, peripheral retina better for low light sensitivity, which is why it helps to not look directly at something dim, but rather to the side.

be very careful about sending vintage watches to omega, this is not generally recommended.

bgrisso

there's lots of discussion about this on the forum, but Omega has it's own idea about what it means to service a vintage watch, which can include replacing parts, etc. They can end up seriously devaluing a vintage watch and ruining the originality and aesthetics. You cannot be certain of control over the decisions they make in servicing.
For this reason, people will usually find a reputable independent watchmaker with an Omega parts account to work on this type of watch.
(If it were a modern Omega, then it might be a different story).

Foo2rama

Luminova- 20 minutes after UV exposure.
Tritium - about 5-30 seconds max after UV.
Radium - no glow after UV exposure once removed.

Do lot send to Omega.

Or Dennis? Have you come home?

Caliber561

I'm skeptical that tritium is the correct answer here. Size of the lume pips and UV testing will tell you nothing.

Every consumer grade Geiger counter I've used on a cased tritium dial has not been able to distinguish any meaningful radiation difference from background. The only time I've had the same Geiger counters act up is with radium watches or thoriated lenses. Also, the 0.5µSv/hr reading sounds about right for a transitional period production article. These Constellations never had much lume to begin with, and by the late 50s manufacturers were using less and less radium.

Caliber561

It's hard to draw any definitive conclusions regarding contamination based on the information you've given thus far. Background radiation does fluctuate, and you haven't been specific with your measurement methods. Geiger counters tend to operate by reporting a running average, so it usually takes a minute or two to get a reading that reflects the actual environment. Additionally, your readings may have been fouled by the setting in which you took them. If you have a granite counter for example, that could skew the results taken on it versus another location. Radium can produce some nasty daughter particles, but I'm skeptical that the outside of the watch would be coated with any sort of radioactive dust. The inside? Maybe.

Caliber561

Plastic is generally made of lighter elements that are less susceptible to neutron activation, so it's unlikely that your crystal is substantially radioactive.

Caliber561

Q2, 3: It's hard to say with any meaningful degree of certainty, even assuming there was some degree of contamination. Great risk? Probably not. You'll want to check out just how high mSv/hr counts can go with commercial flights.

Caliber561

Q4: Your best bet for peace of mind would be to approach a professional watchmaker who specializes in re-lumes. Clearly state that you want to have all of the luminous material removed. You can also ask if the watchmaker offers the option to replace luminous with inert ZnS, which will have a similar custard hue to the original luminous material. Any watchmaker should be able to replace the luminous with modern Superluminova if you want to restore the glow in the dark function.

Caliber561

For what it's worth, OP, I think that it's fair to be concerned about radiation. In some ways, watches can pose more of a risk than other radioactive collectibles like photography lenses and uranium glassware, not because of how radioactive the material is, but because lume binder is very brittle and can result in the luminous material disintegrating into a fine powder that can result in real contamination. As vintage watch cases tend to lose their hermetic sealing, it's reasonable to just not want to deal with something like that.

padders

Get the back taken off and get serial number. The changeover from radium to tritium occurred around the 20,000,000 mark ie 20 million, I wasn’t referring to 20 minutes at all.

Omega changed both dial and hand lume over at that point from radium so a watch would not have left the factory with a mismatch. Of course older hands or a dial could have been retrofitted later but it is not unusual for a dial and hands on a given watch to behave differently despite both using the same lume material as they were usually supplied by different manufacturers.

padders

I personally think you are worrying about nothing here. It looks exactly like pale tritium and the timeline (if you have it correct) matches that. It is very rare for radium lume to remain as pale as yours. Vanishingly so in fact.

Oh and if you send it to omega they will destroy all its character and relieve you of more than it is actually worth. Unless you can get them to keep the dial and hands which isn’t easy. It’s a lovely thing. To swap out what is there would be criminal.

If you seriously can’t cope with the presence of virtually inactive tritium, as Dan bluntly says, sell it and buy something with SL lume and sleep soundly. But never get a plane ride or chest X-Ray again either.

seekingseaquest

Please do not send the watch to Omega, unless you really want a “shiny new” watch. If you want a serviced watch, there are lots of independent watchmakers experienced with vintage watches that will service the watch well and at a much better price, without changing the appearance of the watch.