First, I apologize in advance for the off-topic post...but I couldn't think of any other hobbiyists who might be interested in optics...
I'm looking for some help from you guys, many of whom are likely experts in optical design....
I need to make an optical device to be able to take photographs of the inside of a wood-fired boiler firebox. My problem is that I need something low cost, and most of the industrials I talk to are thinking low cost is $20,000 and up.
I'm thinking of something like a borescope, but simpler--a glass rod, about an inch in diameter by about 4 feet long. The business end would be ground to a wide angle lens shape and the oppose end would be arranged so a digital camera could be attached to it. The rod would be slid down one of the many combustion air ports in the firebox until the business end was flush with the inside of the firebox. It would be held there for a few seconds while photos were taken and then withdrawn.
Presumably the glass rod could be made from some sort of high temperature glass. A thermocouple could be attached to the side of the business end to act as an overheat warning.
The device I am describing sounds not unlike the peephole device put into entrance doors so you can see who is knocking.
However, my knowlege of just how the lensing would need to be arranged is pretty sketchy. Can anyone help or at least point me to some texts that might help? Has anyone seen a device like I am describing?