Circumscribed halo

Circumscribed halo
The upper part of a circumscribed halo.

A circumscribed halo is a type of halo, an optical phenomenon that circumscribes a related phenomenon, the 22° halo centred on the sun.

When observed, a circumscribed halo is normally oval in shape and, at the points directly below and above the sun, lies tangential to the 22° halo. It form when, as the sun rises, the upper tangent and lower tangent arcs extend into each other and close in on the 22° halo.[1] As the sun rises above 70° it essentially covers the 22° halo.[2]

A circumscribed halo is more intense in colour than the 22° halo. Like many other halos, it is reddish on the inner edge, facing the sun, and bluish on the outer edge. [2]

References

  1. ^ Les Cowley (?). "Circumscribed Halo". Atmospheric Optics. http://www.atoptics.co.uk/halo/circum.htm. Retrieved 2007-04-15.  (includes a composite image of a circumscribed halo)
  2. ^ a b "Circumscribed Halo". Arbeitskreis Meteore e.V.. http://www.meteoros.de/arten/ee07e.htm. Retrieved 2007-04-15.  (includes a fisheye photo of the phenomenon)

See also

External links


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • Vädersolstavlan — Infobox Painting| title=Vädersolstavlan artist=Urban Målare, Jacob Elbfas year=1535, 1636 type=Oil on panel height=163 width=110 height inch=64 width inch=43 city=Stockholm museum=Storkyrkan audio|Vädersolstavlan.ogg|Vädersolstavlan (Swedish for… …   Wikipedia

  • Infralateral arc — An infralateral arc (or lower lateral tangent arc) is a rare halo, an optical phenomenon appearing similar to a rainbow under a white parhelic circle. Together with the supralateral arc they are always located outside the seldom observable 46°… …   Wikipedia

  • Upper tangent arc — An upper tangent arc is a halo, an atmospheric optical phenomenon which appears over and tangent to the 22° halo centred around the sun.The shape of an upper tangent arc varies with the elevation of the sun; while the sun is low (less than… …   Wikipedia

  • Lower tangent arc — A lower tangent arc is a rarely observable halo, an optical phenomenon appearing under and tangent to a 22° halo centred around the sun.Just like upper tangent arcs, the shape of a lower tangent arc is dependent on the altitude of the sun. As the …   Wikipedia

  • Tangent arc — can refer to two optical phenomena or halos: * Upper tangent arc * Lower tangent arc See also * Circumscribed halo …   Wikipedia

  • Nevus — A pigmented spot on the skin, such as a mole. The plural of nevus is nevi. * * * 1. A circumscribed malformation of the skin, especially if colored by hyperpigmentation or increased vascularity; a n. may be predominantly epidermal, adnexal,… …   Medical dictionary

  • literature — /lit euhr euh cheuhr, choor , li treuh /, n. 1. writings in which expression and form, in connection with ideas of permanent and universal interest, are characteristic or essential features, as poetry, novels, history, biography, and essays. 2.… …   Universalium

  • Circle — This article is about the shape and mathematical concept. For other uses, see Circle (disambiguation). Circle illustration showing a radius, a diameter, the centre and the circumference …   Wikipedia

  • Spartan army — Military history of Sparta redirects here. For other uses, see Military history of Sparta (disambiguation). The Spartan army was the military force of Sparta, one of the leading city states of ancient Greece. The army stood at the centre of the… …   Wikipedia

  • List of cutaneous conditions — This is an incomplete list, which may never be able to satisfy particular standards for completeness. You can help by expanding it with reliably sourced entries. See also: Cutaneous conditions, Category:Cutaneous conditions, and ICD 10… …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”