subhelic arc
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Subhelic arc — A subhelic arc is a rare halo, formed by internal reflection through ice crystals, that curves upwards from the horizon and touches the tricker arc above the anthelic point. Subhelic arcs are a result of ray entrance and exit through prism end… … Wikipedia
Arc — may refer to: Computing and gaming*Arc (programming language), a Lisp dialect in development by Paul Graham *.arc, a file extension for archive files *arc, the command line interface for ArcInfo *Arc System Works, a video game… … Wikipedia
Parry arc — A Parry arc is a rare halo, an optical phenomenon which occasionally appears over a 22° halo together with a upper tangent arc. Discovery The halo was first described by Sir William Edward Parry (1790 1855) in 1820 during one of his Arctic… … Wikipedia
120° parhelion — A 120° parhelion (plural: 120° parhelia) is a relatively rare halo, an optical phenomenon occasionally appearing along with very bright sun dogs (also called parhelia) as ice crystal saturated cirrus clouds fill the atmosphere. The 120° parhelia… … Wikipedia
