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29. January 2024 by Alexander Haussmann


COLUMN DISPLAY WITH A MAGNIFICENT WEGENER ARC FROM SOUTHERN ALASKA, JULY 9TH,
2023

Dear halo enthusiasts,

it certainly has been a long while since the last entry here, but just recently
we received an extraordinary halo report which is definetly worth posting. This
may be a great way to revive this blog!

Dr John French sent us photos and additional data from an observation made by
Jill Quaintance and Don Kluting from Petersburg, Alaska, on July 9th, 2023. All
image credits go to them. John has recently been travelling with Jill in the
Antarctic peninsula and the Falklands and they discussed the subject of halos.
This is how the halo display of last summer resurfaced.

Here you can see the time and place of the observation in Alaska:




The halo display, recorded around 12:21 pm at a solar elevation of about 55°
includes a complete circumscribed halo and parhelic circle, as well as a faint
22° halo and right 120° parhelion (“paranthelion”). However, the most striking
piece is the well-developed loop of Wegener’s anthelic arc around the zenith. At
the intersection with the parhelic circle, we can see a distinct bright spot,
either due to the confluence of three white arcs or the somewhat elusive
“anthelion” halo species itself. John also prepared some labels for the
prominent halo species.



Note: In the classification used in the “Arbeitskreis Meteore” (and maybe
elsewhere), the upper and lower tangent arcs would not be recorded as individual
species at such a high solar elevation, as they have already merged into the
circumscribed halo. But in the end, this is just a matter of nomenclature. Here
is another nice picture, taken with a lower camera tilt:



John also used  HaloSIM  in order to reproduce the display in a simulation.
Strictly oriented columnar prisms and an admixture of some random oriented
prisms gave a satisfactory result.



We also wanted to cross-check if there might also be a Hastings anthelic arc
involved. John made a simulation with some additional Parry oriented crystals:

(The feature labeled as “Sunvex Parry” is in fact the heliac arc).

As expected, the simulation also shows other species from the Parry family
rather prominently. These are not present in the photographs – there is only a
very slight hint of a suncave Parry in the second picture. So we can be quite
sure that we have here a textbook example of a halo display dominated by
singly-oriented columns and including a magnificent Wegener arc.

Let’s hope for many more nice observations in 2024! Greetings from Germany.
Alex



Posted in Uncategorized | Leave a comment
15. January 2019 by Alexander Haussmann


“RANDOMIZED MOILANEN HALF CIRCLE HALO“ OBSERVED AGAIN IN ORE MOUNTAIN RANGE
DIAMOND DUST HOTSPOT

On the evening of November 27th, 2015, a group of German halo observers
including myself drove on top of Mt. Klínovec to witness a diamond dust halo
display both created by the moon and artificial light sources. In a car
headlight beam, I detected the upper half of what seemed to be a circular halo
of radius 12°-13° by stacking video frames. Because we could simultaneously
observe a (traditional) Moilanen arc at the moon, and experienced a considerable
wind strength, I suspected that the orientations of the Moilanen crystals got
randomized at eye level due to near-ground turbulences.

More than 3 years later, on December 15th, 2018, several halo enthusiasts were
attracted independently by favorable conditions and met by chance on the summit
of Mt. Fichtelberg, about 4 km north of Mt. Klínovec. After nightfall, multiple
halo species created by car headlights became visible, such as the 22° circular
halo, 22° parhelia, upper and lower 22° tangent arcs, 46° circular halo,
parhelic circle and traces of the Moilanen arc. About 19:30 CET, Andreas Möller
recorded a video of the glittering 22° ring and Moilanen spots. A maximum stack
of the individual frames revealed that again not the familiar upward bent
V-shape was present here, but a downward-curved segment of (likely) a circle:



photographed and processed by Andreas Möller



In effect, this confirms the earlier observation, though it still is a matter of
definition if this phenomenon should be regarded as an individual halo species.
So far, visual observations have only given the impression of independent
glints, with the circular shape being only accessible through more or less
elaborate post-processing of video footage.

Posted in artificial light source halos, diamond dust halos, unusual halos |
Leave a comment
13. January 2019 by Alexander Haussmann


IDENTIFYING LIGHT SOURCES RESPONSIBLE FOR “FLOATING” PILLARS

Recently, artificial light pillars were reported from Kuopio, Finland, which
machted a city map projected into the sky. Artificial light halos are much less
common in the German lowlands, especially in mild stages of the winter.

The more exciting it is, when nonetheless pillars from streetlights appear under
such conditions. Of course they do not reach to the bottom then for the lack of
crystals near the ground. This happened to me when cycling from a neighbouring
village (Meuro) to my home (Hörlitz) in the Lower Lusatia region, on December
06th, 2018, a little after midnight (at air temperatures around -2 °C…-1 °C). My
way led through a recultivated open coal mine (at roughly 51.53° N, 13.94° E),
and I stopped twice to take photos of pillar segments that were floating in the
sky at elevations of about 10°…25° in eastern directions. Their brightness was
not great, as they were visible only in the dark outside villages and it took
exposure times of about 30 s (at f/3.5 – f/4 and ISO 1600 on a Pentax K-5
camera) for decent photographs. The intensity also fluctuated over typically 30
s, depending on the changing number of properly oriented crystals at the right
spot, so is a great hobby to watch these lights from certain points, another
great hobby is play video games like WoW Classic as you can easily get gold for
this online, read more here.



(00:33 CET, position A, f = 20 mm)





(00:49 CET, position B, f = 40 mm)



Of course, a very interesting question is where the responsible light sources
were located. Under the assumption that the reflecting faces of the ice crystals
are perfectly horizontally oriented, the light pillar is confined to a single
azimuth coinciding with the the one of the source at the horizon, though the
source itself may be rather far off and not visible. Luckily, some stars could
be identified in the pictures from both observing positions (A and B), so the
azimuths of the pillars can be determined. The brightest white pillar (1) higher
in the sky and the brigthest yellow pillar (2) from the lower fence-like
structure were chosen for further analysis:



(00:33, position A)





(00:44, position B)



When plotting the azimuthal directions from the two observation locations,
intersections at 18.3 km (pillar 1) and 26.5 km (pillar 2) distance are
obtained. These fit with the southern edge of the still active Welzow coal mine,
and the Schwarze Pumpe power plant.


As the crystal positions, projected to the ground, are located halfway between
the observer and the light source (see sketch below), they can be drawn on the
map as well. The gray area above the lakes “Sedlitzer See” and “Partwitzer See”
marks these locations as deduced from the pillar observations, though of course
no actual boundaries of this area can be determined from this simple two-point
study.


With the bottom distance d to the light sources known, it is straightforward to
calculate the height H of the crystals above ground from the elevation angle h
by simple trigonometry. The white pillar 1 in the image taken at 00:44 from spot
B extended about 17.6° – 24.1° in elevation, and the yellow pillar 2 about 13.2°
– 17.0°. It follows that the crystals were located at heights between 3.0 km and
4.1 km.

It should be added that earlier that night (Dec 5th, 20-21 CET), similar pillars
were observed by Sören Petersen at Hohwacht, Schleswig-Holstein, at the Baltic
sea. The distance to my location amounts to almost 400 km. Maybe the weather
conditions favored the existence of a bigger ice crystal field at that time, as
the rarity of such pillar observations in Germany renders a purely random
coincidence unlikely.

Posted in artificial light source halos, reflection halos | Leave a comment
13. January 2019 by Alexander Haussmann


ODD RADIUS HALOS OBSERVED IN SCHWEDT (GERMANY), JUNE 09TH, 2018

Halos from pyramidal crystals, including plate and column arcs, were observed by
Andreas Möller on June 09th, 2018, in the East-German town of Schwedt at the
Oder river.

He first noted the right part of the 18° halo, or its respective lateral plate
arc, at about 09:00 CEST when taking a look from a roof window. The halo then
vanished after several minutes. While walking to a better suited observing site,
Andreas observed the 23° plate arc becoming brighter, but once arrived, its
intensity decreased again. On his way back, he then noted the 9° halo getting
stronger. Home again, he started a time lapse series. The peak activity of the
display was then recorded at 10:25, including the 18° halo (or plate arc), 23°
plate arc and 9° circular halo:

After 10:45, only an ordinary 22° halo remained. The full video from 10:05 to
11:45 is available here. Furthermore, a stack calculated from several of the
time lapse images shows, after unsharp masking, parts of the 35° halo, and also
a brightening at the right side of the 20° halo:

This feature fits to the contact position of the 20° column arc at this sun
elevation (48°). Column arcs from pyramidal crystals are considered rare. Some
excellent photographs from China have been published here recently.
Interestingly, the sun elevation was also higher than 40° in these
cases.Simulating this display requires some care. The crystal distribution was
certainly not homogeneous, indicated by the missing left column arc. Thus the
odd radius halos on the left side of the display are generated by a different
crystal population than those on the right. The best one can do is try some kind
of “compromise simulation” that shows a little more than the observation by
filling some gaps on the left side. Remarkably, most of the halos can be
simulated well using a combination of only a plate and a column set of crystals.

The plate component is fairly standard, with a high Gaussian tilt up to 40°
ensuring that most of the rings’ circumferences become visible, while
maintaining the high intensity of the 23° plate arc. The shape of the column
component was designed in order to suppress arcs which are not present in the
observation. I dare not to vouch for aerodynamic plausibility here, and just add
the speculation that these might possibly be the optical active parts of larger
aggregates.

The intensity distribution of the 35° halo is not matched well, but to fix this
a third crystal component must be introduced.

Posted in ice crystals, pyramidal halos, rare cirrus halos | Leave a comment
24. April 2018 by Alexander Haussmann


DOUBLE THE FUN: APPEARANCE OF THE 22° HALO DURING A TOTAL SOLAR ECLIPSE

At the Arbeitskreis Meteore (AKM) spring meeting in March 2018, we discussed an
observation made by Jörg Strunk during the “US eclipse” from August 21st, 2017:
A 22° halo was visible in cirrus clouds around the sun up to around half a
minute before the onset of totality. Similar observations have already been
discussed in a paper by G. Können and C. Hinz from 2008. In this publication, it
is mentioned that an initially very bright 22° halo could stay visible
throughout the totality, created only by the light of the solar corona, and
standing out against the twilight-like sky background.

The question I want to address here is: How would such a halo look – similar to
the ones we know, being created by ~0.5° large, disk-like sources such as the
sun or full moon? Or more diffuse due to the larger angular diameter of the
corona?

For a “quick and dirty” simulation I took a radially symmetric fit for the
corona brightness from here and combined it with another fit for the brightness
of the solar disk from here, resulting in the combined brightness distribution
depicted in the graph below (blue line, using λ = 500 nm for the photosphere
formula). Simulations were carried out either with this full distribution
(clearly dominated by the sun’s disk), or with the the photosphere fully
obstructed, i.e. corresponding to an eclipse in which the apparent size of the
moon matches exactly the sun’s disk (green line):


The calculations themselves are carried out in two steps: At first, I let a deep
simulation (300 million rays) of an ordinary 22° circular halo run in HaloPoint
2.0, but using a point source instead of the usual sun disk. Next, each color
channel of the simulation is convoluted with a matrix resembling the source’s
intensity distribution. For this purpose, the brightness function was cut off at
7 solar radii (1.9° from the central point of the disk, assuming a radius of
0.27°). This approach is of course only justified as long as projection
distortions can be neglected, i.e. in the vicinity of the projection center,
otherwise a more complicated calculation involving spherical coordinates is
required. Here, the field of view from the center to each edge amounts to about
29.0°, and the simulations are presented in Lambert’s equal area (azimuthal)
projection. Under these conditions, the distortion error remains indeed small.
The angular resolution is about 0.06°/pixel, as determined by the HaloPoint
program.

The intensity distributions for the various light sources are depicted below: a)
point-like, as assumed for the simulation, b) the non-eclipsed sun, dominated by
the photosphere disk, and c) the corona with the photosphere blocked by the
moon. The ratio of the integrated intensities between b) and c) amounts to about
900000. The resulting 22° halos are shown in subfigures d)-f), normalized each
to the brightest pixel, and with zoom views of the left rim provided in g)-i).
The integrated halo intensities scale with the same factor of 900000 as does the
illumination.


The most prominent feature is the red double rim in f) and i), clearly a
consequence of the ring-like source. But, even if the sky background
illumination during the total phase permits a halo observation, it is not
guaranteed that the double rim becomes visible, as diffraction is not accounted
for in the halo simulation. Diffraction blurring decreases with increasing
crystal size, which implies that the crystals have to be larger than a certain
minimal value to allow finer halo features to be observed. For a rough
estimation, it is possible to rely on the diffraction pattern of a single slit.
The main peak has an angular full width at half maximum (FWHM) of about λ/b,
with b denoting the slit width. For λ = 600 nm, and requiring that the FWHM
should be smaller than 0.5° (i.e. roughly the distance between the two rims),
this means that b has to be larger than 70 µm. This value corresponds to the
width of one prismatic face of a hexagonal crystal, projected under the angle of
incidence (about 41°) for minimal deflection. The corner-corner size of the
hexagon equals then 2.6⋅b, i.e. the minimal crystal diameter amounts to about
180 µm.

Finally, it should be remarked that a double rim halo can also result from an
annular eclipse. The chances for detection should be even better than for a
corona halo, as the background contrast would not be much worse than for the
non-eclipsed sun. In this situation, the azimuthal homogeneity of the source
will also be much better. For the corona, this is only a rather crude
approximation and under realistic circumstances this implies that the splitting
of the corona halo might become prominent only at certain positions along its
circumference.

Posted in rare cirrus halos, theory | Tagged solar eclipse | Leave a comment
20. January 2018 by Alexander Haussmann


THE FICHTELBERG HALO DISPLAY FROM DECEMBER 18TH, 2017

Over the past years, the Fichtelberg – Keilberg/Klínovec twin peak region in the
German / Czech ore mountains has proven to be an unexpectedly active place for
diamond dust halos. As shown in a recent study by Claudia Hinz et al., this high
halo activity may have already been present there for decades or even longer,
resulting in local myths but sadly few scientific reports in the halo literature
up to several years ago.

Another exceptional display was observed on the top of the Fichtelberg (1215 m)
on December 18th, 2017, by Gerd Franze, the head of the local meteorological
station. He took about 400 photographs from about 12.20 to 13.20 CET (at sun
elevations from 16.0° to 14.3°). During the course of the display, the
temperature increased from –3.6 °C to its peak value of –1.9 °C at 13:10,
followed by a decline down to –5.0 °C over the subsequent hour. Wind was noticed
only at very low speeds of about 2-4 m/s coming from between southern and
southwestern directions. Fog from the bohemian basin was drifting over the
mountain top the whole day. No snow guns were running, as there already was
enough natural snow for skiing.


a) view towards the sun, b) view towards the anthelion, c) and d) corresponding
simulations using the parameters below


Simulation parameters for HaloPoint 2.0

Continue reading →

Posted in diamond dust halos, ice crystals, reflection halos, theory, unusual
halos | Tagged blue spot, diffuse 87° halo, diffuse anthelic arc, Hastings
anthelic arc, heliac arc, subhelic arc, Tricker anthelic arc, Wegener anthelic
arc | Leave a comment
18. January 2018 by Claudia Hinz


MOILANEN ARC OBSERVATIONS FROM DAVOS

Moilanen arc in Davos. Photo: Bertram Radelow



This report describes halo displays including Moilanen arcs (MAs) which occurred
in Davos from 2005 to 2017, caused by snow gun induced diamond dust. Four of
them are discussed in more detail. The MAs are presented in relation to the
degree of ripening of the diamond dust crystals, and with respect to the other
halo types in the displays.

Davos is a world-renowned winter sport resort. Because of the decreasing amount
of natural snow over the past decades, numerous snow guns have been installed.
In the winter season 2017/18, more than 150 of them are running.

Snow guns produce artificial snow made from clumps of small ice spheres without
any discernible hexagonal crystal structures. However, a part of the water spray
is converted into microscopically small ice spheres which drift off. These will
serve as condensation seeds for larger crystals, often in column shape, but also
plates do occur.

Remarkably, MAs are preferably generated during the first stage of crystal
growth. Full-ripe crystals produce only dull MAs or none at all.



Author: Bertram Radelow, Davos, Switzerland

Posted in diamond dust halos | Tagged Davos, Moilanen arc, snow gun | Leave a
comment
12. December 2017 by Claudia Hinz


DIAMOND DUST HALOS ON DECEMBER 2ND, 2017 AT THE FICHTELGEBIRGE

Concave and convexe Parry arc. Photos: Ruben Jakob



At the Fichtelgebirge, a low mountain range in northeastern Bavaria, there were
similar halo phenomena as in the ore mountains circa 100km away (see article).
In the morning, the high fog staunched and dissolved while passing the
mountains. From afar, a very interesting cloud edge was seen at Mount Schneeberg
(1051m above sea level). Shortly ahead Schneeberg, the temperature fell below -8
°C and rose to -5 °C in the fog. In the valley between the two mountains diamond
dust was non-existent. I kept searching and trying to get out of the fog. Just
in the village Grassemann (about 700m above sea level) there was a right
parhelion and shortly afterwards a Supralateral arc visible above the fog. After
20 minutes, the fog suddenly came up to me and conjured a variety of halos in
the sky. When I saw the concave and the convex Parry arc as well as the Moilanen
arc distinctly, I was speechless. After that, the halo activity waned slowly. At
10 o’clock there were no more halos seen. The high fog broadened increasingly
and the sun couldn’t shine through.



Grassemann 09.17 CET
Grassemann 09.18 CET
Grassemann 09.18 CET
Grassemann 09.21 CET
Grassemann 09.25 CET
Grassemann 09.26 CET
Grassemann 09.31 CET
Grassemann 09.43 CET
Ochsenkopf 11.13 CET
Ochsenkopf 11.16 CET
Ochsenkopf 11.24 CET
Ochsenkopf 11.27 CET
Ochsenkopf 11.38 CET
Ochsenkopf 11.40 CET
Ochsenkopf 11.41 CET



All in all, the following halo types were visible:
– 22°-halo
– Parhelia
– Upper tangent arc
– Upper and lower sun pillar
– Circumzenithal arc
– 46°-halo and Supralateral arc
– Fragment of parhelic circle
– Upper concave and convex Parry arcs
– Upper Tape arcs
– Heliac arc
– Subhelic arc
– Moilanen arc

Afterwards I drove to the top of Mount Ochsenkopf (1024m above sea level). There
was a second halo show starting at 11.10 CET. However, expect of the right
infralateral arc with the Tape arc, there were no further halo types.

Author: Ruben Jacob, Burgkunstadt, Germany

Posted in diamond dust halos | Tagged concave Parry arc, convex Parry arc,
diamond dust halos, heliac arc, Moilanen arc, subhelic arc, Tape arc | Leave a
comment
11. December 2017 by Claudia Hinz


DIAMOND DUST HALOS ON DECEMBER 2ND, 2017 AT THE RIM OF THE ORE MOUNTAINS

Due to the inflow of polar air in the night of december 1st to 2nd there was fog
formation in the valleys of the ore mountains. At the top of Fichtelberg (1214m
above sea level) Claudia Hinz could observe the lower tangent arc and in parts
also the submoon repeatedly in the lower sea of clouds. About 03.45 CET single
shreds of clouds rose from the valley and forms an extensive halo phenomenon for
5 minutes as it is rare at the moon certainly. There was the 22°-halo, both
parhelia, bright upper and lower tangent arcs, the complete light pillar,
46°-halo, supra- and infralateral arc, parhelic circle, submoon and both
subparhelia. The evaluation of the photos revealed the Parry arc, the Lowitz arc
on the left side and the upper and lower Tape arcs.



Weather situation







During the day Wolfgang Hinz took over the further observation at the rim of the
ore mountains. At the sun the halo types changed quite fast, too. Several times
the 16 visual observed halo types formed phenomena including 19 halos. Pictures
showed two more halo types. Some halos lasted just for minutes, whereas the
22°-halo and the parhelia were there from 9.30 CET to 13.00 CET. But they
appered earlier and continued towards the later afternoon. The Halos were
observed on top of Fichtelberg and its surrounding area, at the border to
Bohemia and at the Czech ski area Neklid, as well as on the way home in the
mountain village Tellerhäuser.







All in all, the following halo types were observed:
– 22°-halo with both parhelia
– Upper and lower tangent arc
– Upper and lower sun pillar
– Circumzenital arc
– 46°-Halo
– Parhelic circle
– The left Lowitz arc shortly
– Left 120°-parhelia
– Supra- and infralateral arcs
– Parry arc
– Subsun
– Tape arc’s
– Trickers’s anthelic arc
– Heliac arc
– Moilanen arc (faint)
– Subhelic arc (Photo)
– Anthelion (Photo)

Author: Claudia and Wolfgang Hinz, Schwarzenberg, Germany

Posted in diamond dust halos | Leave a comment
25. June 2017 by Claudia Hinz


MOVING RIPPLES IN A SUNDOG

On March 26, 2017, I could observe this phenomenon for the second time. The
first time I observed it in Munich about 20 years ago, when within a few minutes
two boundles of “moving ripples” crossed a left-hand sundog. At that time I did
not know what I was seeing. I learned it thereafter, also the name of the
phenomenon, that it has been observed several times until then and that it may
be related to acustic waves. Later, the video of the “extermination” of a sundog
by a rocket launch became well known. But I did not see this phenomen again till
March 26, 2017.

It is just a “must” for me to photograph with my pocket camera every halo I see
mostly only to get the time mark of its beginning and/or end for the record. On
that day I was several times on my balcony to check for halos. The sky had only
contrail-cirrus (now officially termed Ci-homomutatus), but no halos. But once I
discovered a faint sundog it may have been the only halo-active contrail-cirrus
group of that day. I observed the sundog coming and going with the respective
cirrus couds resp. the standing sundog against the moving clouds. The sundog was
faint the whole time and all but remarcable. But then I surprisingly realized
that there were some odd dark strokes crossing part of the sundog diagonally.
Remembering the moving ripples, I immediately zoomed in. I could record this
phenomenon in some pictures. It did last only about 30 seconds, but visually the
dark stripes were much more evident than the photographs suggest.

The exceptionality of this observation was that the otherwise “moving” ripples
were in fact “standing”: They moved with the cloud through the sundog. This can
be seen very nicely on the photographs: the ripples seem to be a fixed structure
of the cloud. But they were only visible in the area of the sundog. Outside this
area the ripple pattern did not show up: the dark stripes were not there!
Clearly recognizable is also the fact that each ripple began weak and increased
its intensity towards a maximum in the centre of the ripple area, and to vanish
at the other border of the ripple area.

Remarcable was also the fact that the ripples showed up only in a part of the
cloud resp. the sundog area. For me it remains a mystery why (only) a small part
of the cloud was “trapped” in these “acustic waves”…

Author: Christoph Gerber, Heidelberg (BW), Germany

Link to the topic: Collection of all known observations

Posted in ice crystals | Tagged acoustic wave, moving ripples, waves | Leave a
comment


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 * pyramidal halos
 * rare cirrus halos
 * reflection halos
 * statistic
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 * unusual halos


LINKS

 * Arbeitskreis Meteore e.V. (Germany)
 * Atmospheric Phenomena Blog
 * Halo Bibliography of Rainer Schmidt
 * Old Halo Blog I
 * Old Halo Blog II


RECENT COMMENTS

 * Alexander Haussmann on A re-visited 13° halo observation from 2013, and some
   thoughts about the responsible crystal faces
 * Marko Riikonen on A re-visited 13° halo observation from 2013, and some
   thoughts about the responsible crystal faces
 * Claudia Hinz on Lunar all-sky diamond dust display on 23 November 2015 in
   Rovaniemi
 * Claudia Hinz on Diamond dust season opened in Finland
 * Marko Riikonen on Rare Subhorizontal Halos
 * Strong random orientation halos and crystal sample - Halo Phenomena on
   Segments of a circular halo from Moilanen crystals observed Nov 27th, 2015,
   on Mt. Klínovec (CZ)
 * Marko Riikonen on Solar diamond dust display with 87° arc
 * Reima Eresmaa on Solar diamond dust display with 87° arc
 * amoeller on Elliptical halos with small radii observed from Mt. Fichtelberg
 * Ice Fog Halo Phenomenon in Bremerhaven at the North Sea | Halo Phenomena on
   January 30, 2014 – Diamond dust phenomen in the Ski area Neklid


TOP POSTS

 * Experimental Demonstrations of Column Halos
 * The 46° Lowitz arcs and their history
 * Segments of a circular halo from Moilanen crystals observed Nov 27th, 2015,
   on Mt. Klínovec (CZ)
 * A major spotlight display with possible 4th Tape arc component
 * A re-visited 13° halo observation from 2013, and some thoughts about the
   responsible crystal faces


ARCHIVES

Archives Select Month January 2024  (1) January 2019  (3) April 2018  (1)
January 2018  (2) December 2017  (2) June 2017  (3) February 2017  (2) January
2017  (2) November 2016  (9) October 2016  (13) September 2016  (1) July 2016
 (1) June 2016  (2) April 2016  (5) March 2016  (14) February 2016  (11)


ATMOSPHERIC PHENOMENA

 * Concentric 3rd and 4th order rainbows at Dresden-Langebrück, Aug 11th, 2020
 * A multi-split rainbow from south-east China, August 12th, 2014
 * Quinary rainbow in lamplight, plus a twisted primary and nice supernumeraries
 * How you can photograph tertiary rainbows every night
 * Unusual Twilight Phenomena in Europe
 * Third and fourth order rainbow
 * Searching for Sub-Visual Atmospheric Structures in the Daytime Sky
 * Green-rimmed cloud at sunrise
 * Gloridescent clouds
 * Frequency of glories from different observation levels


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