No one ever replied - which is understandable given that I now know what happened. I switched to using the Omegon Pro driver, which works fine. After updating to 3.6.9 I figured the toupcam driver for my installation should be repaired and had another try - with the same weird result.

But, when I checked the statistics in fits viewer (which I guess I had not done when it first showed up), I had separate R G and B stats. The problem, as it turns out, was that my toupcam driver had somehow set to RGB mode instead of RAW-16. How? Who knows. But it is fixed now.

Read More...