A divergent-light 22° halo from a Long March 6A reentry

Around 19:51 (UTC+8) on 4 June 2026, the RedNote user "岚烟喵喵喵" (ID:6109395002) photographed a bright divergent-light 22° halo at Qishui Bay, Hainan (19.6416°N, 110.9883°E). The light source was probably the reentering stage of the Long March 6A (Y25), which shone through high clouds about twelve minutes after lifting off from Taiyuan Satellite Launch Center at 19:39. The strong divergence made the 22° halo appear noticeably distorted rather than circular (Fig. 1). No precise orbital data was available for the reentering stage, thus an approximate trajectory was reconstructed from the government maritime navigation warning (Qiong Navigation Warning 82/26)¹ and from image fitting. 

Fig. 1 Frame 300, showing the divergent 22° halo

The trajectory reconstruction here is rough. No aerodynamics are used. It is a purely geometric back-projection with drag and reentry deceleration ignored, so this is an approximate trajectory. There is only one viewpoint, so the direction to the source is constrained but its distance is not. And the fit was done by eye, so errors are large.

The observer was located at Qishui Bay from terrain in the video and the RedNote post, with a small cove ahead of them matched against Google Earth to find the coordinates (19.6416°N, 110.9883°E) as shown in Fig. 2. Because the event was at night and low over the sea, no calibration stars were available, so the camera was calibrated against the terrain instead. SRTM 30 m DEM data gives the three-dimensional coordinates (latitude, longitude, height) of the surrounding landscape. Manually aligning the terrain outline visible in the video, the two small hills on the left, with the DEM-rendered terrain solves for the camera's field of view and pointing. Once calibrated, any pixel in the frame can be converted to an azimuth and elevation.

Five pixels along the glowing track were measured this way, giving five sightlines. The debris is assumed to move along a straight line in space. However, single-station angles cannot fix the distance scale. The official drop zone was therefore used as the trajectory endpoint, and the distance to the debris at each of the five points was then solved by least squares. The fitted points have a collinearity residual of about 1.3 km, which is small compared with the roughly 200 km range, although it should not be interpreted as a formal uncertainty. The result places the glowing reentry low in the east-southeast, at roughly 70 to 34 km altitude and 230 to 195 km away. This still rests on the assumption that the path is a straight line.

Fig. 2 Google Earth view of the observation site, matching the terrain in the video

The light passed through a layer of high cloud between the observer and the reentry. Himawari-9 cloud data for the nearest time (11:40 UTC) in Fig. 3 shows the sightlines crossing cirrus with tops around 13 to 15 km and an optical depth of roughly 0.5 to 1.4. This supports the presence of a suitable high-cloud layer.

Fig. 3 Himawari-9 cloud-top height at 11:40 UTC 

The parallel-light halo data was generated with ZHANG Jiajie's Lumice, and the divergent-light display was then computed from it using Lefaudeux's method². Because of the poor quality of the original video and the presence of only a 22° halo, the simulation used a single regular hexagonal crystal habit with a c/a ratio of 2.5. Several simplifications should be noted. The simulation accounts for neither the brightness of the light source nor that of the halo, and the optical transmittance of the cloud plays no role in it. The ice crystals are assumed uniform throughout the cloud layer, which was set between 13200 and 14700 m, with a maximum simulated distance of 300 km from the observer. The result is therefore meant only to show that the halo geometry matches the video, not as a precise photometric comparison. As can be seen in Fig. 4, the simulation aligns fairly well with the observation. 

Fig. 4 Frame 303 with the simulation result

Elevation 10.37°, distance 195.8 km

In divergent light, the crystals that can send 22° halo rays have positions that form an elongated cigar-shaped locus between the eye and the source, known as Minnaert’s Cigar⁴. A flat cloud layer therefore cuts this locus in different ways depending on the source elevation and distance.

Divergent-light halos from natural high cirrus are rare; a case illuminated by a rocket reentry seems even more unusual. A closely related case was published very recently by Haussmann³, in which a bright fireball produced a 22° halo whose radius was shrunk to about 20° by divergent effect. In that case, however, the source was near the zenith, so the cirrus layer cut Minnaert’s Cigar almost straight above and the halo remained circular, only smaller. Here the source was low in the sky, so the cloud layer cuts the cigar obliquely. This is the slanted-cut case that Haussmann³ pointed to as probably not yet observed, and it distorts the halo rather than simply shrinking it. It should be noted that no measurement as accurate as Haussmann's was possible here, since there was no simultaneous parallel-light halo in the same frame to serve as a reference. 

The Hainan event is only one of many possible divergent-light configurations. As the source elevation, distance, and halo type vary, the Minnaert cigar is cut in different ways, producing shapes that have rarely or never been recorded. To show how sensitive these forms are, I include a few simulations below.

Fig. 5 shows an animated 22° halo with the source at 30 m distance and the cloud top at 100 m, the cloud base rising from 0 to 3 m, and the elevation set to 0°. The halo shrinks into a "light ball".

Fig. 5 22° halo, source distance 30 m, cloud top 100 m, cloud base rising from 0 to 3 m

Fig. 6 shows odd-radius halos, with an elevation of −1°, a distance of 100 m, and a cloud layer from 0 to 5 m.

Fig. 6 Divergent odd-radius halos

Fig. 7 shows the diffuse halo of raypath 3-5-6-7-3, at elevation −25.6°, distance 100 m, and a cloud layer from 1 to 30 m. The halo takes two forms, one surrounds the whole horizon, the other looks like a normal diffuse halo. Here the cigar subtends such a large angle that it looks like a "tomato" (Fig. 8). Raypath filtering was applied.

Fig. 7 Divergent diffuse halos

Fig. 8 A "cigar" with a radius of 140°

All these examples assume the crystals are arranged in infinite flat layers. In reality the crystals can be distributed in very different and interesting ways, such as on windshields, where the halo shapes depend dramatically on the lamp elevation and the windshield's position between observer and source⁵. Marko Riikonen has captured many such windshield cases, including elliptical halos and reflection-view displays⁶.

An interactive HTML file is provided, allowing the simulation to be viewed together with the video, with tools to let the user experiment with the Minnaert's cigars. The original video and the simulation images are also included in the link.

https://drive.google.com/drive/folders/1Z8f5_HufUhPua_f9Rq92FNDS316jD3Cz?usp=sharing

Acknowledgements. I thank the Chinese halo community for help in reaching the original poster, Sedimentary-Cloud (沉积云) for help with the divergent-light simulation, and SONG Xi Pei for help with the rocket data. The original video is used with permission from the observer. AI assistance was used in programming and some other parts of this work.

References

¹ Qiong Navigation Warning 82/26, Maritime Safety Administration of the People's Republic of China (Qinglan MSA), issued 3 June 2026. https://www.msa.gov.cn/html/cnmsa/hxaq/article/2026/808345637af44bf3831ab02000ecc176.html

² N. Lefaudeux, "La simulation des halos divergents / Divergent light halos simulation", opticsaround, 27 July 2013. https://opticsaround.blogspot.com/2013/07/la-simulation-des-halos-divergent.html

³ A. Haussmann, "Divergent light effects in ice crystal halos created by fireballs: a case study of a 22° halo with a 20° radius," Appl. Opt. 65, C42–C47 (2026). https://doi.org/10.1364/AO.582021

⁴ J. O. Mattsson, L. Bärring, and E. Almqvist, "Experimenting with Minnaert's Cigar," Appl. Opt. 39, 3604–3611 (2000). https://doi.org/10.1364/AO.39.003604

⁵ W. Tape, "Windshield Halos," in Streetlight Halos (2010), Chapter 13. https://scholarworks.alaska.edu/uaf_mathstats_facpubs/3/

⁶ M. Riikonen, "26/27 Jan 2026, Rovaniemi… elliptical halo," X. https://x.com/RiikonenMarko/status/2016261603444793506

Mikkilä's Soul in high cloud

Hello from Japan,

On March 28, I observed an anthelic pillar while flying over Wakayama in Japan. This was unexpected, as there were no reports from the ground that day of anything other than a 22° halo. Four stacked images were created from 71 photos captured over a three-minute period.

17:29:26–17:29:35 12 frames  ave USM

17:29:39–17:29:59 10 frames

17:30:03–17:30:27 22 frames

17:30:28–17:30:53 23 frames

Aircraft altitude: 9,000 m; Sun elevation: 8.71°

At first, I thought this was a diffuse arc, but it did not match the simulation, as shown below.

As I pondered, I came to think of Mikkilä's Soul as a possible answer.

Another one was Robert Greenler’s alternative Parry orientation model. Let us consider this first, as it can be simulated easily.

An appropriately tilted alternative Parry orientation produces a pillar that is brightest at the anthelic point.  If we assume that the upper part is missing owing to the absence of cirrus clouds, this pillar appears to be consistent with the observations to some extent.

That said, this explanation is unrealistic. Assuming this is Mikkilä's Soul, I first tried to identify the diffraction fringes. However, neither B-R nor BGR showed any fringes. I also checked the single frames to rule out possible misalignment in the stacking process, but the results were the same.

 

The length of this pillar is 20° ± 1°, which raises the question of whether Mikkilä’s Soul can really be this long. The answer lies in the 2021 Åre display. If the Soul extended to the subanthelic point, it must have been at least 20° in length.

thehalovault.blogspot.com

Since there is no other plausible explanation, this can be considered to be Mikkilä's Soul. 

The Soul is virtually unknown in Japan and has never been observed there before. This could be the first observation.

 

Now then, does the Soul really shine brightest at the subanthelic point? The image below shows the moment the Soul’s brightness peaks at the subanthelic point. However, it seems even brighter somewhat below the anthelic point.

Is this simply due to the cloud’s unevenness? In the fourth image, both the subanthelic and anthelic points are clearly located within the same cloud. Further understanding of the Soul requires simulation.

 

As a side note, on August 19, 2025, I photographed a 120° subparhelion along the same flight path.

Supreme light pillars ('city maps') - 2026.5.3, AnQing, China.

 Between 23:00 and 24:00 (UTC+8) on May 3, LIU Qian Yu(刘乾煜) captured a supreme light pillars event occurring within high-level clouds(or falling virga in middle-level) in Anqing City, Anhui Province, China. The clarity of the observed 'mirrored city streets' map' is very very distinct and remarkable. JIA Hao and I consider this record to be among the most outstanding documentations of such phenomena worldwide. 

BGR+USM

As an experienced astrophotographer and member of the Chinese ice halo community, LIU promptly switched to an circular fisheye lens, thereby capturing a full view of this sky wonder. A meteorological chart corresponding to approximately three hours offset from the time of photographic observation is attached, with our appreciation extended to QIAN Kun for supplying this chart. 

Song Xi Pei contributed to the comparative works between LIU's image and maps.

I used Google Maps and Tencent Maps respectively to compare with the perspective transformed image.

Discussions on a former observation from the Pic du Midi observatory (France) on 2003, March 29th

 

        During a coronagraphic mission of one week at the Pic du Midi observatory (altitude: 2,877 m), Marie-France Balestat and Frédéric Guinel had the opportunity to observe a conjunction of atmospheric optical phenomena – see Figure 1.

 

   

Figure 1. All of these two pictures show, behind the cables, a coloured glory (which is not complete, because of the shadow of the tower and of the cupola of the coronagraphs) and over, at the same azimuth, a white anthelic pillar in a cloud above the horizon. © Marie-France Balestat

 

         A preliminary remark: while the pillar is due to oriented ice crystals in the air, the glory (accordingly to its rotational symmetry) is due to tiny water droplets. Crystals and droplets could coexist in the same cloud, but only transitorily: the crystals pumps water of the droplets (a phenomenon known as the Bergeron effect, described in 1933), because the tension of vapour in equilibrium with the corresponding solid is lower than with the corresponding supercooled liquid at the same temperature.

However, to explain the conjunction shown by Figure 1, the luck to photography just during such a transitory moment isn’t necessary, because it is clear on the pictures that the two clouds, respectively producing the glory and the pillar, are obviously distinct – the first cloud is near and slightly below the observer, while the second cloud is much farther and above the observer.

 

        Let us now focus on the white pillar, also visible on another picture – see Figure 2. 

 

 

Figure 2. The same anthelic pillar (and, on the right, the Pic du Midi cable car station)
© Marie-France Balestat

 

 

Being on the opposite half of the sky with respect to the Sun, this cannot be an ordinary reflected Sun pillar. Two main possibilities remain open:

a)      the foot of the Y produced with a low Sun by a diffuse-B arc (a refractive halo, presenting apparent achromatism);

b)   Mikkilä’s soul – a retrodiffractive halo having the form of an anthelic diffraction pillar, discovered in 2012 by Marko Mikkilä, and explained later by Nicolas Lefaudeux.

 

Let us compare the features of these two haloes a) and b), and illustrate them by photographs already published in the Halo Vault.

 

a)      Diffuse-B arc [1]	b)     Anthelic diffraction pillar – “Mikkilä’s soul”
On this photo above, due to Marko Riikonen (2008, November 6th), a careful examination reveals the presence of the 2 arms characteristic, for a Sun height between 2° and 8°, of the Y given by a diffuse-B arc – see the last row of [1]. On Figures 1-2 we do not guess any Y, but this could be due to the uneven present cloud (on these Figures, with a too weak apparent vertical extent of the ice cloud). No irization is perceptible, despite the dispersion due to refraction; this is coherent with the apparent achromatism – also presented, among the family of anthelic arcs [1], by the Tricker and diffuse-A arcs, but not by the Wegener arc (see Figure 3).	. Neither on the original image above, due to Minna Kinnunen (2021, November 8th) nor with the treatment (below, due to Nicolas Lefaudeux) we see any Y of a low-Sun diffuse-B arc.  The treated image reveals a bright central fringe, accompanied by lateral fainter fringes, as usual in diffraction. A notable fact is the absence of visible diffraction irizations (comparatively with coronae); it could be due to the heterogeneity of the crystals size, coherent with the low-contrast and small number of the diffraction fringes.
The radiance maximum seems to be on the anthelic point – which is coherent with its nature of double point for all the anthelic arcs [1].	The extrapolated radiance maximum could be on the subanthelic (aka antisolar) point – which is coherent with the retrodiffractive nature of Mikkilä’s soul. This isn’t obvious on Figures 1-2, but it could be due, once more, to the uneven cloud visible on these Figures.

 

As a temporary conclusion, according to the criteria and the remarks above, until further information or image treatments it is not possible to decide whether the white pillar shown by Figures 1 and 2 is a fragment of diffuse-B arc, or of Mikkilä’s soul partially blurred because of a notable heterogeneity of the crystal sizes; it could also be a combination of these two haloes.

 

Appendix: on the effect, in the family of anthelic arcs, of ice / air chromatic dispersion

In hexagonal columnar ice crystals, the sequence of two refractions and one reflection producing the Wegener arc does not yield the property of apparent achromatism, contrarily to the sequences (with more reflections) producing the Tricker and diffuse-A and B arcs respectively [1]. This is coherent with the fact that, on the superior part of the Figure 3 that shows a Wegener arc, a red irization is clearly visible on the lower side of this arc – the Sun being at the height of the parhelic circle seen on the inferior part of this Figure.

Figure 3. From top to bottom: a Wegener arc (with a reddish lower rim) and a parhelic circle with a paranthelic point (also known as 120° parhelion) – which both present, accordingly to the theory, the property of apparent achromatism. The anthelic point is outside the frame, on its right, accordingly to the inclination of Wegener’s arc. © Marko Mikkilä (2007, September 9^th)

 

Reference

[1] R. G. Greenler & E. Tränkle, « Anthelic arcs from airborne ice crystals », Nature 311, 339-343 (1984) – see Figure 1.

Posted by Luc Dettwiller