How does my telescope "see through" a flag?

I was aligning the spotter with the eyepiece to an antenna on a faraway mountain and a nearby flag was fluttering in-between the scope and the antenna. The flag obscured the antenna in the spotter about 80% of the time, however, in the scope, the antenna was visible 100% of the time! I could see it through the flag. The flag was still there, but the flag was transparent! So cool. Is it because of the light-gathering power of the 11"? Like does it just suck the light through the flag? I would love a good explanation! thanks!