 |
 |
 |
| Halos over Bulgaria imaged at Cherni Vrah (Black peak), Vitosha Mountain near Sofia by Nikolay Stoilov. ©Nikolay Stoilov, shown with permission. |
|
|
|
|
 |
About - Submit | Optics Picture of the Day | Galleries | Previous | Next | Today |  |
| Two types of ice crystal produced this display. Hexagonal plate crystals generated the bright circumzenithal arc (CZA). The down curving much fainter arc touching the CZA is a supralateral arc produced by sun rays passing between the side and end faces of horizontal column crystals. |