New Feature Sitrec: Simulating Halos and Sun Dogs

[Giddierone]

Might it be possible to simulate atmospherics like sun dogs?

 

[Mick West]

I shall put my team of robots on the task!

 

[Mick West]

Do you have a specific test case?

 

[Mick West]

Done!

Version 2.84.0 (2026-06-15)

New Features

• Atmospheric Optics (Halos) (Lighting → Atmospheric Optics (Halos)): renders ice-crystal sky optics around the real Sun and Moon — a 22° halo, sun dogs, circumzenithal and circumhorizontal arcs, parhelic circle, 46° halo, sun pillar, and upper tangent arc by day, plus a faint Moon halo and moon dogs at night. Each effect only appears at the Sun or Moon elevation where it physically forms, and fades cleanly at the horizon. Turn it on with Show Halos (off by default).

https://www.metabunk.org/sitrec/?custom=99999999/Halo Test/20260615_195836.js

https://www.metabunk.org/sitrec/?custom=99999999/Moon Halo/20260615_195943.js

 

[Giddierone]

Do you have a specific test case?

Well, I was going to ask if strange atmospheric phenomena might eventually be simulatable in sitrec.

The case I was thinking of is the 2007 Alderney Case (https://www.metabunk.org/threads/the-alderney-ufo-sighting.12149/) which at least one observer thought could have been a sun dog. (The report David Clarke's contributed to is here: https://www.nicap.org/reports/070423channel_islands.pdf)

But was also thinking about this after reading Menzel's chapter "The Great Saucer of 1882" (attached as a PDF) there seems to be a bit of similarity between the cases (although one is after sunset and the Bowyers is early afternoon).

Maunder's account features in Charles Fort's Book of the Damned (1919)

E.W. Maunder, invited by the Editors of the Observatory to write some reminiscences for the 500th number of their magazine, gives one that he says stands out (Observatory, 39-214). It is upon something that he terms "a strange celestial visitor." Maunder was at the Royal Observatory, Greenwich, Nov. 17, 1882, at night. There was an aurora, without features of special interest. In the midst of the aurora, a great circular disk of greenish light appeared and moved smoothly across the sky. But the circularity was evidently the effect of foreshortening. The thing passed above the moon, and was, by other observers, described as "cigar-shaped," "like a torpedo," "a spindle," "a shuttle." The idea of foreshortening is not mine: Maunder says this. He says: "Had the incident occurred a third of a century later, beyond doubt everyone would have selected the same simile—it would have been 'just like a Zeppelin.'" The duration was about two minutes. Color said to have been the same as that of the auroral glow in the north. Nevertheless, Maunder says that this thing had no relation to auroral phenomena. "It appeared to be a definite body." Motion too fast for a cloud, but "nothing could be more unlike the rush of a meteor." In the Philosophical Magazine, 5-15-318, J. Rand Capron, in a lengthy paper, alludes throughout to this phenomenon as an "auroral beam," but he lists many observations upon its "torpedo-shape," and one observation upon a "dark nucleus" in it—host of most confusing observations—estimates of height between 40 and 200 miles—observations in Holland and Belgium. We are told that according to Capron's spectroscopic observations the phenomenon was nothing but a beam of auroral light. In the Observatory, 6-192, is Maunder's contemporaneous account. He gives apparent approximate length and breadth at twenty-seven degrees and three degrees and a half. He gives other observations seeming to indicate structure—"remarkable dark marking down the center."

Menzel thought the observation made by professor Maunder was "some unusual form of auroral activity".

There's some similarity in the descriptions:
Maunder (1882) described "a very elongated ellipse", "cigar-shaped", "like a torpedo" and "like an enormous baseball bat"
Bowyer (2007) described a profile "like that of a thin cigar suspended horizontally", a "very flat platform" and "cylindrical".

Maunder said the object had "a clearly defined outline, but a plain uniform surface".
Bowyer said the object had a "very sharply defined edges and pointed ends"

Both described the objects as exceptionally bright:
Maunder: "many times brighter than the Northern auraral glow", "pearly white" to "yellow white".
Bowyer: "very bright yellow object" "self luminous rather than reflective" and "brilliant but not dazzling"

Both mention some kind of internal marking:
Maunder: a "remarkable dark marking down the center", "internal shadow ranging from dullness to a dark nucleus parallel to the long axis"
Bowyer: "a dark graphite grey patch" approx "2/3 of the way from the left hand end, like a narrow band around a cigar"

Bonus coincidence: the observer who thought Bowyer's sighting could have been a sun dog was also called... Maunder

A local astronomer, Michael Maunder, attributed Bowyer's report to sun dogs, an optical phenomenon caused by the refraction of light through ice crystals in the atmosphere.

from Wikipedia).