Sub-Liljequist and probable 'sub-Liljequist Blue Spot' in high cloud above China

 

The sub-Liljequist 'Parhelion' in high-clouds is rare. On August 14, 2025, a user '太平洋蓝藻'(ID: 516836436) from ' Bilibili.com'(a polular vedio website of China) captured the first record of this event in China during a flight over the Yellow Sea. the sub-Parhelic Circle and sub-120° Parhelion were captured at the same time.

What makes this particularly remarkable is that on left of sub-Liljequist 'Parhelion' in the photograph shows a distinct blue tint, suggesting the possible presence of 'sub-Liljequist Blue Spot'. Pinson HUANG from the Chinese halo watching community was the first to identify this possibility and made the initial simulations. I refined the simulation parameters based on HUANG's work, and the results showed a good alignment with the photograph. SUN Hao Xuan(孙浩轩) and Jing Xiang from the Chinese halo watching community assisted in image authorization and joined in the related research process. KiloNova(千新星), SONG Xi Pei and QIAN Kun from the same community provided crucial information in the analyses of flight data and lens characteristics.

 

The photograph was taken at 16:43:26 (UTC+8). Based on the CZ5855's flight information(N37.96, E122.98) retrieved from https://flightadsb.variflight.com for that specific time, it can be further concluded that the solar altitude was 22.3 degrees.

The unevenness of cloud layer should be considered as the cause of the unevenness of the sub-PC, but some simulation results quite support the existence of the sub-Liljequist.

Halos on windshield

Tonight there was a diamond dust display that had parhelia and pillars. Later I went back out and happened to walk past my Dad's car where I saw a long curve of bright sparkles on the windshield. I took a closer look and saw subparhelia. I got my flashlight out and that is when the fun began. I placed the light on the hood and got bright, colorful and clear subparhelia along with a diffuse subparhelic circle. I also held the light high above and got circumhorizontal arc as well. The diamond dust I kind of messed it up with the lens being slightly out of focus. I didn't realise this until I got to look at the pics on my screen.

A plate spotlight display on 5th November 2016

By Marko Riikonen

Showcasing the last winter’s spotlight displays is still under way, but fresh produce is already coming in. Here is the new crop that I harvested on the evening of 5th November in Rovaniemi. In the image above the lamp is around -6 degrees below the horizon and both parhelic and subparhelic circle are visible. Slight intensity enhancements in them on the side of the sky opposite to the lamp are suggestive of Liljequist parhelia. Included are also Sub-Kern and sub-120° parhelion. I did not spot sub-Kern this time, but the latter was quite discernible when running alongside the beam. As usual, it was a pale pillar of light in which no individual crystals were detectable – very different from the intense subparhelic circle patch towards the subanthelic point, which is always made of pure glitter.

The display disappeared immediately when it got cloudy and there was nothing to be had for the rest of the night. What is not visible in any of the photos, but what was there many times during the display was the subanthelic diffraction pillar. Discovered by Marko Mikkilä in 2012, it is a quite basic feature in plate displays, but tends to come and go, never lasting long. So it is not necessarily captured by the camera unless you take it as your target.

The temperature was around -10 and -11 °C at the location. It is in a typical range of good plate stuff, not yet too cold.

One display - three mysteries

By Jarmo Moilanen and Marko Riikonen

It is difficult to get a matching simulation of pretty much any spotlight display. Some details tend to be always wrong. But one can usually obtain what could be called an acceptable approximation of the real thing.

The shown display is a true rebel in this respect, for it comes with three anomalies too blatant to be swept under the rug. First, the subparhelia were brighter than parhelia (this we noticed also visually). Second, of the Schulthess arcs (the arcs from Lowitz orientation) only the concave component was visible. And third, there is no subparhelic circle opposite to the lamp.

We can not simulate any of these anomalies. The solitary presence of the Schulthess arc concave component is not a new thing, there exists a handful of such displays. The missing of subparhelic circle opposite to the lamp in this level of display is something unheard of, as is the inverted relative brightness of parhelia and subparhelia. In the simulation above (light source elevation -5 degrees) only plate oriented crystals were used. Below is a sample of the simulation crystal shape variation, the “mother shape” shown in the upper corner.

The display had also a weak segment of parhelic circle between subparhelia. The crystal shape shown above struck the right balance between the sub-Kern and the parhelic circle segment inside subparhelia.

The night was 18/19 January, the location the Sieriaapa bog in Rovaniemi. The temperature was – 29° C.

Catching a divergent light halo effect predicted by simulations

Sometimes it is possible to make a deliberate attempt to photograph something predicted by simulations. On the night of 6/7 January we made such an attempt on the diffuse spots of light that in simulations are seen next to the divergent light subparhelion.

The effect is formed by a mixture of subparhelic circle raypaths, including 3157 raypath and sub-120° parhelion raypath. Its exact shape and position depends significantly on the crystal shape, like for the Liljequist parhelia.

To obtain an omnidirectional secondary light source that was bright enough we pointed the lamp directly to the snow surface. We took photos, looked at them more closely the next day, and there it was – those smudges of light predicted by simulations.

The photo above is actually from a slightly better case on the night of 18/19 January. Next to it is a simulation. Below is the one on the 6/7th.

Nicolas Lefaudeux / Marko Riikonen / Jarmo Moilanen / Marko Mikkilä

Diamond dust halos on the night of 12/13 January, part III

Has anyone seen subparhelic circle inside subparhelia? Neither have I. Not before stacking the photos from the latter part of the 12/13 January night. In one of the stacks this missing segment is seen faintly inside subparhelia. The version of the image above, made by Nicolas Lefaudeux, was done with emphasis on getting the segment stand out as clearly as possible.

Below is a more conventional looking version of the image and simulation. The plate oriented crystals in the simulation were fully triangular. Regular hexagons do not make the missing segment, except at very high light source elevations.

What else? The arcs that in Finland these days are called the Schulthess arcs are quite well defined, especially in the last photo set of the night (below). One sees both concave and convex components extending from subparhelia to parhelia, though the latter component seems to have a gap around the horizon, not reproduced by the simulation. I have never seen in sun display photos the concave component between parhelia and horizon. It is always just the convex component that is visible.

Marko Riikonen

Subhorizon diffuse arcs with Liljequist subparhelia

Francesco De Comité took this great photo from an airplane between Brussels and Madrid in 7 August 2006 at 19h31. Unfortunately no more additional photos are available from this display.

There is really well developed diffuse anthelic arcs crossing subparhelic circle. Subanthelion point is illuminated by these arcs. In this case it is clear that there is no subanthelion, since bright spot on subanthelion point has clearly square shape caused by diffuse arcs. Column ice crystals have to have good orientation.

Other very rare halo shown in this photo is broader segments on parhelic circle on both sides on subanthelion point. Unfortunately these broader segments are not very clear and they are cutted by edges of the photo. These broader brightenings are so called Liljequist subparhelia caused by plate ice crystals. Liljequist subparhelia have been photographed earlier at least by Walter Tape (see Tape's book Atmospheric Halos in page 71). Tape's display is very similar than this Francesco's display.

Since Francesco's display has rare halo made by plate ice crystals, it would be a really good case to look for still undocumented 120° subparhelia. Hunt for 120° subparhelia is still going on...

Subparhelic circle

On June/3/2006 at 20:20 CEST Susanne Danßmann observed a subparhelic circle on a flight from Berlin to Zurich. The elongated spot of light in the center of the image is likely a subanthelion. The shadow on the winglet suggests the photo was taken in direction of the antisolar point. There is no shadow of the airplane in the center of the subanthelion, because the airplane was high above the clouds.