Solar Arcs and Halos . ... Credit Copyright: Eva Seidenfaden Explanation: Have you ever seen a bright halo around the Sun? Unusual halos and arcs were so bright one recent afternoon in Trier , Germany that even casual people on the street noticed them. The fantastic sky display is pictured above and included a 22 degree halo arc , a complete parhelic circle , a circumhorizon arc and even an infralateral arc . ... NASA Web Site Statements, Warnings, and Disclaimers . ...