Been trying to help others build eFinders (aka Digital Finders). Biggest difficulty is finding a telescope or lens that has the right focal length and is fast, about 200mm f/2 would be ideal but really expensive.
A friend has a Starlight Lodestar guide camera which he wants to use and this has a ‘c-mount’ thread. This made me look at cctv lenses. I found a good 50mm f/1.8 lens and took the plunge and tried it.
It produces decent enough images in about 0.5 to 1 second exposures which is great. The field of view is 4 degrees on my camera which is bigger than I wanted but still means the pixel size in about 15 arc sec, so plenty of accuracy on plate-solves.
