When ice crystals are present in the atmosphere halo's can appear in different forms like arcs, rings or bright spots. Under "perfect" conditions, even a complex halo display can show up. Besides the common ones (like parhelia/sun dogs and 22° halo), also the more rare ones can be visible. On May 6 2011, such complex display could be witnessed for over than half an hour with no less than 7 different halo's at the same time. The common halo's were: two bright spots or parhelia (1) in the parhelic circle (2), the 22° halo (3) with on the top upper tangent arc (4) and finally also the circumzenithal arc. The two rare ones were: Parry arc (as rather faint suncave feature on top of the upper tanget arc) and a huge & bright colorful supralateral arc (with touching circumzenthal arc). The supralateral arc is often mistaken for a 46° halo, but one of the indicators for being a supralateral arc is when 22° halo is rather faint and upper tangent arc very bright, and such was the case in this shot.

In the picture you can move the mouse over picture to see the description.

More pictures of optics via link