Editing the Lens Flare?

I am thinking of using something similar to the lens flare in the TestLensFlare class, but it doesnt really do what i want…

i am using the flare in place of a sun, but when a corner just barely covers the center, everything disappears except the sphere which is the sun object. is there some way i can change the code in the associated classes or within my code to keep this from happening.

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any ideas?