Seeing T2 reticle during star sight

I don't have the answer, but that reminds me of an anecdote...

When I was at Ft. Sill the star shot training was conducted in a totally blacked out room. A large plexiglass circle, painted black and back lighted, had been attached to the minute hand of an old clock movement and had the constellations scratched into the paint so they shone through. It was actually a pretty good simulation of the movement you have to get used to in order to get a good shot. Anyone who has been there will remember "tracking, tracking, tracking, TIP". The toughest thing was trying to figure out if you had the proper star on every shot.

Anyway, while we were in there one day someone was fooling around and shone the red-lensed note keeper's light through the eyepiece. A perfect projection of the crosshairs appeared on the star-clock, allowing perfect sighting without even looking through the scope!

We began recording some of the best sets EVER!!

The illumination for the T-2 reticle comes from the vertical circle light path- - is the vertical path illuminated bright enough? (you can hold a flashlight up to the side of the theodolite, shine the light through and turn the knurled illumination knob on the top (like you've been doing)- if the light path is clear you should be able see the reticle.)

In the picture below, light to illuminate the reticle comes from the left (#6) through the vertical circle and is reflected 45deg up to the eyepiece at #9. The reflection occurs by turning the knurled knob on top of the telescope, which is connected to a small mirror- (not identified in this drawing, but it's the object shown in the middle of the telescope at the intersection of light rays from #6 and #9 ) -

It may be that you need more illumination. The mirror adjustment is probably not as reflective as when new.

I have a light attachment for a Nikon-Gurley instrument. If not adjusted properly it will not illuminate enough. The bulbs do not appear to be as bright as I remember and the batteries have a short use span.

Try using a brighter flashlight and shine into the receptical (hole) or upgrade to a brighter bulb.

On a transit we would have someone to shine a light from an angle across the objective lens and that would illuminate the crosshair.

A Surefire flashlight will certainly do the job ... might singe the hair on the back of your head, though. When my students comment that "I can't see the crosshairs" when I am teaching collimation, a few seconds with a Surefire cures their problems. Of course, I illuminate a piece of paper obliquely - certainly not directly along the optical axis.

Not having the proper illumination attachment for my GTS-2B, I can shine a flashlight in the port but don't get uniform illumination and see lots of dirt in the view that doesn't show up when looking through the scope any other way. Does the proper illuminator do something with focus to avoid this problem, or do I just have a dirty piece in the optics?

I tried attaching a cheapo tiny LED book light, filtered red, with the 1/2" dia light assembly hanging in front of the objective lens. It only blocked a small part of the objective field of view, and was out of focus so I got nice illumination. I seemed to find up to 20 sec of error one way or the other depending on where the thing was in the field of view. I didn't expect serious refraction. Is this a well-understood problem? Is it related to parallax?

I would not think it's parallax. My guess is that the chrome deposition lines on the glass reticle might reflect BACK onto the other side of the glass reticle and you were mistakenly pointing on its reflection rather than on the crosshairs themselves.

That is what is called a SWAG. (Scientific Wild-Ass Guess)

I tried removing the Wild light and pointing a flashlight in the
hole,and I was able to see the reticle. Next I'll try a brighter
bulb in the Wild light.