To be clear, you're requesting a material that is optically thin in the narrow range of EM radiation that is human visible but relatively opaque otherwise. Obvi

To be clear, you're requesting a material that is optically thin in the narrow range of EM radiation that is human visible but relatively opaque otherwise. Obviously particle radiation in general is just blocked by matter. However transmutation the material undergoes has to /also/ maintain these properties. I can't think off the top of my head why it would be /impossible/ but it'll definitely be an engineering nightmare compared to good camera feeds and a few scattered "Star Park" type facilities.