Ngauruho webcam

I was just having a look at a few volcano webcams & happened upon this one at Ngauruho. New Zealand Nothing going on but the sun in the photo has a black circle in the middle of it & I wondered why? can anyone explain?

I have saved a picture and if I manage to put it on the page all good & well but here is a link to the webcam site they have all the latest pictures.

www.world-cams.be...