My new (to me) Panda arrived last evening. A very clean example, circa 1977. Although I’m no expert, it appears to be a correct, original example. Unfortunately, the lumed hands and indexes no longer illuminate…which is surprising as the original lume on my 1969 Omega Constellation still functions…albeit not very brightly.

 

Nice, love the panda dial. Wear in good health.

 

Very nice, that's a classic. Tritium lume from the 70s has generally become quite dim since the half-life of tritium is 12 years, so it's normal that it is no longer luminescent. Is your Constellation passively luminescent in a dark room? Or are you referring to what happens when you stimulate the dial with visible or UV light? That depends a great deal on the particular phosphor.

 

Looks so nice. Wear in good health!!

 

Congratulations! It looks like it could be much younger, obviously a timeless design

 

After I “charge” the Constellation’s lume by placing it directly under and close to light source…and then bring it into a dark room…it’s lume shows…dimly.

 

Yes, that is just the phosphor, and different formulations were used at various times by different manufacturers. Some have degraded chemically while others remain active. Regarding "dead" lume more generally, as you probably know, these dials originally glowed in the dark without any need for "charging" by light because the phosphor was excited by the radioactive decay of the tritium.

 

lovely watch, it is is in great condition too

 

that it is