I have just installed two 6" little red neon lights into my observatory. They are quite bright so may need to hide them from direct view. They were actually designed for cars and inside computers, but work great as Observatory lights. Bought them from ****Smiths.
NO main power to the dome, I wouldn't trust full time AC in the observatory yet until it's fully insulated and weather proof, although it is, I would like to see it more weather proof.
I gave it a run lastnight, and although bright, the lights did help quite a bit moving around in the dark and reading maps.. I am running them off a 12v jump start pack which I use to run the fans on the scope too.