parhelion n : a bright spot on the parhelic circle; caused by diffraction by ice crystals; "two or more parhelia are usually seen at once" [syn: mock sun, sundog] [also: parhelia (pl)]
Etymologyparelion ← παρηλιον ← παρα- + ἡλιος.
A sun dog or sundog (scientific name parhelion, plural parhelia, for "beside the sun") is a common bright circular spot on a solar halo. It is an atmospheric optical phenomenon primarily associated with the reflection or refraction of sunlight by small ice crystals making up cirrus or cirrostratus clouds. Often, two sun dogs can be seen (one on each side of the sun) simultaneously.
Sundogs typically, but not exclusively, appear when the sun is low, e.g. at sunrise and sunset, and the atmosphere is filled with ice crystal forming cirrus clouds, but diamond dust and ice fog can also produce them. They are often bright white patches of light looking much like the sun or a comet, and occasionally are confused with those phenomena. Sometimes they exhibit a spectrum of colours, ranging from red closest to the sun to a pale bluish tail stretching away from the sun. White sundogs are caused by light reflected off of atmospheric ice crystals, while colored sundogs are caused by light refracted through them.
The ice crystals causing atmospheric phenomenon are shaped as hexagonal prisms (ice Ih, e.g. with a hexagonal top and bottom and six rectangular sides). Some of these crystals are elongated, some are flat; the latter causing crisp and bright sundogs if evenly oriented with their hexagonal ends aligned horizontally, while the former produces other atmospheric phenomenon, such as parhelic circles, 22° halos, circumzenithal arcs, upper tangent arcs, and lower tangent arcs. A mixture of various crystals with different alignments produces several of these phenomena at the same time.
When the sun is low, the two sundogs are located on the circle of the 22° halo. As the sun rises, the sundogs slowly move along the parhelic circle away from the sun, finally, to vanish as the sun reaches 61° over the horizon
On Earth, the first planet (counting from the sun) with significant amounts of ice crystal-carrying clouds, the pair of sundogs flanking the sun are aligned with the horizon. On other planets and moons where water and ice are less prevalent, however, various crystal structures produce different halos. On the giant gas planets—Jupiter, Saturn, Uranus and Neptune—other crystals form the clouds of ammonia, methane, and other substances that can produce halos with four or more sundogs.
EgyptThere are records among the writings of the Ancient Egyptians that discuss two suns in the sky, and one that discusses the sun setting in the east, or moving backward.
GreeceAristotle (Meteorology III.2, 372a14) notes that "two mock suns rose with the sun and followed it all through the day until sunset." He says that "mock suns" are always to the side, never above or below, most commonly at sunrise or sunset, more rarely in the middle of the day.
CiceroA passage in Cicero's On the Republic (54-51 BC) is one of many by Greek and Roman authors who refer to sundogs and similar phenomena: Be it so, said Tubero; and since you invite me to discussion, and present the opportunity, let us first examine, before any one else arrives, what can be the nature of the parhelion, or double sun, which was mentioned in the senate. Those that affirm they witnessed this prodigy are neither few nor unworthy of credit, so that there is more reason for investigation than incredulity.
Wars of the RosesThe prelude to the Battle of Mortimer's Cross is supposed to have involved the appearance of a complete parahelion with three "suns". The Yorkists took them to represent Edward of York, George of Clarence and Richard of Gloucester and their impending victory.
Jakob HutterPossibly the earliest clear description of a sun dog is by Jakob Hutter, who wrote in his Brotherly Faithfulness: Epistles from a Time of Persecution: My beloved children, I want to tell you that on the day after the departure of our brothers Kuntz and Michel, on a Friday, we saw three suns in the sky for a good long time, about an hour, as well as two rainbows. These had their backs turned toward each other, almost touching in the middle, and their ends pointed away from each other. And this I, Jakob, saw with my own eyes, and many brothers and sisters saw it with me. After a while the two suns and rainbows disappeared, and only the one sun remained. Even though the other two suns were not as bright as the one, they were clearly visible. I feel this was no small miracle … The observation most likely occurred in Auspitz (Hustopeče), Moravia in very late October or very early November of 1533. The original was written in German and is from a letter originally sent in November 1533 from Auspitz in Moravia to the Adige Valley in Tirol. The Kuntz Maurer and Michel Schuster mentioned in the letter left Jakob Hutter on the Thursday after the feast day of Simon and Jude, which is October 28. (This quote is also referenced by Fred Schaaf on page 94 of the November 1997 and December 1997 issues of Sky and Telescope.)
While mostly known and often quoted for being the oldest colour depiction of the city of Stockholm, Vädersolstavlan (Swedish; "The Sundog Painting", literally "The Weather Sun Painting") is arguably also one of the oldest known depictions of a sun dog. For two hours in the morning of April 20 1535, the skies over the city were filled with white circles and arcs crossing the sky, while additional suns appeared around the sun. The phenomenon quickly resulted in rumours of an omen of God's forthcoming revenge on King Gustav Vasa (1496-1560) for having introduced Protestantism during the 1520s and for being heavy-handed with his enemies allied with the Danish king.
Hoping to end speculations, the Chancellor and Lutheran scholar Olaus Petri (1493-1552) ordered a painting to be produced documenting the event. When confronted with the painting, the king, however, interpreted it as a conspiracy - the real sun of course being himself threatened by competing fake suns, one being Olaus Petri and the other the clergyman and scholar Laurentius Andreae (1470-1552), both thus accused of treachery, but eventually escaping capital punishment. The original painting is lost, but a copy from the 1630s survives and still can be seen in the church Storkyrkan in central Stockholm.
Nuremberg, Germany in 1561On April 14 1561, the skies over Nuremberg, Germany were filled with a multitude of celestial objects that were observed by many people in the city. The objects were depicted five years later in the 1566 woodcut by Hans Glaser of the "1561 Nuremberg event", that is displayed to the right. Several of the images resemble the types of phenomenon that occur as parhelia.
ShackletonIn her history Shipwreck at the Bottom of the World: The Extraordinary True Story of Shackleton and the Endurance, telling the story of Endurances ill-fated polar expedition in 1912, Jennifer Armstrong writes: … All around them, too, were signs that the Antarctic winter was fast approaching: there were now twelve hours of darkness, and during the daylight hours petrels and terns fled toward the north. Skuas kept up a screeching clamor, and penguins on the move honked and brayed from the ice for miles around. Killer whales cruised the open leads, blowing spouts of icy spray. The tricks of the Antarctic atmosphere brought mock suns and green sunsets, and showers of jewel-colored ice crystals.
In fictionA reference to 'parhelia' occurs in the Introduction to Vladimir Nabokov's 1962 novel Pale Fire: The short (166) Canto One, with all those amusing birds and parhelia, occupies thirteen cards.
In the fifth novel of the Aubrey–Maturin series, Desolation Island, Patrick O'Brian writes: A visit to the cabin showed him the glass lower still: sickeningly low. And back on the poop he saw that he was by no means the only one to have noticed the mounting sea – an oddly disturbed sea, as if moved by some not very distant force; white water too, and a strange green colour in the curl of the waves and in the water slipping by. He glanced north-west, and there the sun, though shining still, had a halo, with sun-dogs on either side. Ahead, the aurora had gained in strength: streamers of an unearthly splendour.
In her popular historical novel about Richard III of England, The Sunne in Splendour, Sharon Kay Penman writes: Hastings laughed, too, and shook his head. 'Men do make their luck, Lady Margaret, and never have I seen that better proven than at Mortimer's Cross. For ere the battle, there appeared a most fearsome and strange sight in the sky.' He paused. 'Three suns did we see over us, shining full clear.'
In a footnote it is clarified: "Phenomenon known as a parhelion, generally caused by the formation of ice crystals in the upper air."
Two pages later, again mentioning the English king Edward IV, she adds: "Many, she saw, flaunted streaming sun emblems to denote her son's triumph under the triple suns at Mortimer's Cross."
Sundogs appear in the film The Deer Hunter. At the beginning of the film, as the men are leaving work, they see the phenomenon. Robert De Niro's character describes it as an 'old Indian thing' and "A blessing on the hunter sent by the great wolf to his children".
Sun dogs are referenced metaphorically in Rush's 1989 classic hit "Chain Lightning" on the album Presto. Neil Peart has been quoted as saying that they are "an inspiration for his lyrics."
The band Of Montreal used the image in the lyrics to "The Past Is a Grotesque Animal" on the 2007 album Hissing Fauna, Are You the Destroyer?:
I've played the unraveler, the parhelion But even Apocalypse is fleeting There's no death, no ugly world
Jack London has a short story called The Sun Dog Trail.
One of Robert Rauschenberg's early experiments in 1962 employing the silk-screen process to reuse previously published images in "Combine Paintings" is titled "Sun Dog".
- Sundogs - Parhelia, Explanations and Images, Les Cowley's Atmospheric Optics site
- Optical Phenomena - Photos of sun dogs
- Starry Night Photography - Sun Dog, Sun Halo, Moon Halo - Some photos and some text
- Atmospheric Optics - Ice Halos
- Sundog Splendor! video with marvelous close-ups
parhelion in Catalan: Parheli
parhelion in Danish: Bisole
parhelion in German: Nebensonne
parhelion in Spanish: Parhelio
parhelion in French: Parhélie
parhelion in Italian: Parelio
parhelion in Hebrew: כלבי השמש
parhelion in Latin: Parhelium
parhelion in Dutch: Parhelium
parhelion in Japanese: 幻日
parhelion in Norwegian: Bisol
parhelion in Polish: Słońce poboczne
parhelion in Portuguese: Parélio
parhelion in Romanian: Halou
parhelion in Russian: Паргелий
parhelion in Swedish: Vädersol