Tritium Illuminated Reticle Eyepiece

[cataclysm]

This thought came to my mind when I was toying with the idea of marking my equipments in the field with a more reliable light source that negates the use of battries. Better still, if I can find some small enough, would be able to insert them into crosshairs eyepiece, which I did.
Managed to get hold these tiny 5mm TGLS (tritium gas light source) vials or more commonly known as Beta Light from a shop at Funan. It was sold as a keyring and encapsulated clear cylindrical plastic, requires some careful cutting to extract the tiny vials.
Beta light illumination has a widespred application in military optics, but yet to came across any manufacturers producing them for astronomy. So I experimented it on my good old 9mm Meade Plossl and it really works!!

Here are some pictures:

The vials are really tiny, just 5mm in length x 1.5mm diameter, really delicate to handle.


The Meade eyepiece has a centering optical block with etched reticles, this is where I inserted the luminous vials.


Requires 2 vials for sufficient illumination. As compare to original red LED illuminator, they are still quite a fair bit dimmer.

Success!! Took this directly through the ocular with my camera and macro lens, with 30s exposure in a dimmed room.

[Gary]

OMG! Cool! Tony Stark in the making!

[Bergkamp_]

headshot!!

[alweek]

Genius! Did the eyepiece have slots in the side for the tritium tubes or did you cut them?

[Clifford60]

Kelvin, be careful now that the TGLS is outside the protective holder, never crack it. Also hope that you after seeing a long time thru the eyepiece, your eye don't turn green. hahaha

Anyway, great idea, just make sure you protect the TGLS.

[cataclysm]

Genius! Did the eyepiece have slots in the side for the tritium tubes or did you cut them?

Hi alweek, yes I cut the slots with Dremel cutting tool, and the vials are properly secured with clear epoxy.

[cataclysm]

Kelvin, be careful now that the TGLS is outside the protective holder, never crack it. Also hope that you after seeing a long time thru the eyepiece, your eye don't turn green. hahaha

Anyway, great idea, just make sure you protect the TGLS.

Hi Clifford, thanks for the safety reminder. Indeed the Tritium is mildly radioactive ( essentially beta particle ), but even when the vials are broken, the radiation is too weak just to penetrate your skin. Inhaling, ingesting it may pose a higher health risk, but at that minuscule amount, you have to ingest a lot of them to pose any health risk. By now, the vials are securely set, firmly embedded within the reticle block with clear epoxy.

[weixing]

Hi,
Nice DIY job. Had you try in a real dark environment? Just wonder will the light leak into the FoV? Anyway, I think a red one might better... ha ha ha

Have a nice day.

[cataclysm]

Hi Weixing, yet to try it on an actual dark site, but I think it will work. There is some light leak, but the illumination is so feeble that it hardly affect the contrast of the viewing. Agree that red light would be more ideal, but their output is very dim, only about 20% as bright as the green. As you can see from the pic, I actually needed 2 green vials to provide sufficient illumination.