The Moon nighttime with a moon IS an infinate shadow dumbasses so yeah i think itll be crazy shadow stitching every direction...... a flash bomb.would make light also soo
i'd guess it would be stronger at night. Considering that photons are still there even at night. the problem would be if his body is casting a shadow.
if his shadow is still there even at night then he can use it. Its size is dependent on what light source he's blocking. But since he showed the ability to control shadows that dont belong to him(shadow of the stadium during exams) i can't see why he cant control the shadow of the earth if his shadow is apart of it.