A strange spot appeared on the inner side of the right 22° Parhelion. Obviously, it was not any odd radius halo.
To me, the reason for this phenomenon is the diffraction and interference of light. The USM images seems to support this speculation.
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These rare images were taken by ZHANG Jin Rong from the Chinese sky enthusiasts' community (in BeiJing, on January 1, 2026, from local time 15:50 to 15:56).
Several years ago, when the "multiple CZA" was discovered, it was also considered extremely rare. But nowadays, at least dozens of people around the world have captured the "multiple CZA". Perhaps, in the near future, more diffracted 22° parhelia will be recorded. Now I'm already looking forward to the discovery of the diffracted CHA. Anyway, what a crazy New Year gift for 2026!
Wow! It's once again the Chinese halo magic at play. Kudos for Zhang having captured this.
ReplyDeleteParhelion is a much photographed halo, so how come only now? Maybe the answer is in the cloud, which looks like Ac lenticularis. It is not virga, it is the cloud itself. I don't know any other halo display with such origin. But then again, we have several cases of the multiplied zenith arc in more normal looking cloud. Should the same crystals that make these make also multiplied parhelia?
Yes, there are Lenticular clouds at about 3500~4000m altitude.These lenticular clouds are dissipating in a special form - turning into very thin As undulatus in the horizontal direction. In Beijing, this occurs at most once a year on average. Over the past decade or so, I may have only seen a few similar incidents.
DeletePlate crystals need to be very small to form interference fringes that are distinct enough, but small plate crystals are hard to keep nice orientation. For CZA, the degree of optical intensity diffusion caused by the tilt is not as severe as that of 22P, which might be one of the reasons why multi-CZA is more common. In addition, I think there is another possible reason why multi-22P is rarer than multi-CZA. That is, if the plate crystals are very thin, the interference fringes it cause will extend much more in the vertical direction than in the horizontal direction. This is beneficial for people to observe multi-CZA but not to multi-22P.
interesting and unusual observation indeed. the diffraction of the parhelion light by the crystal seems a good explanation.
ReplyDeletefor this to happen, it does not require very small crystals, but rather very homogeneous lateral size of crystals.
in terms of size, the diffraction pattern of a square aperture is a sinc. i quickly tried to estimate the angle of the zero of the sinc seems to be about 0.75° from the main lobe (parhelion), in the green channel. that gives aperture size around 40µm. ie crystals about 100µm diameter, which is actually "average" size crystals.