[spel_grammer_an_punct_polise]

I had always been intrigued as a child about little magnifying glasses that would make grass, leaves or twigs catch fire.

If the Germans were thinking of some kind of focused beam or parabolic dish I’m afraid that the concentrated rays of the sun would burn up the parabola.

[staytrue]

the sun’s rays are quite diffuse.

all spacecraft receive direct sunlight and do not burn up.

the parabola would receive diffuse rays and the rays would only be concentrated at the focal point of the lens.

only at the focal point will there be burning rays.

[BipolarBob]

As a child, I was amazed to find out that ants would spontaneously combust as I was studying them under my magnifying glass.

[thackney]

I had always been intrigued as a child about little magnifying glasses that would make grass, leaves or twigs catch fire.

If the Germans were thinking of some kind of focused beam or parabolic dish I’m afraid that the concentrated rays of the sun would burn up the parabola.

Just like with the magnifying glass, the concentration of the light doesn't happen at the parabola, it happens at the focal point away from the parabola.