© George Anderson

Derbyshire, United Kingdom of Great Britain and Northern Ireland

Latitude: 53° 6' 0'' N

Longitude: 1° 23' 24'' W

16 April 2009 0730 (Local Time)
Camera direction: towards E

Image P/S code: P.13.1.7

Image I.D.: 3810

• Images & related info Other Images Images of 1987 edition
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  Subsun

  The subsun, or undersun, is a halo phenomenon produced by the direct reflection of sunlight on ice crystals in clouds.

  The subsun can only be viewed when looking downwards, and is only observed from aircraft or mountains. It appears vertically below the Sun as a brilliant white spot, similar to the image of the Sun seen on a calm water surface.

  The bright subsun at the centre of this photograph was viewed from an aircraft flying above Cirrus cloud over England. Low pressure was to the southwest of Britain and a cold front was over the south of the country.

  The ice crystals responsible for a subsun are typically horizontally orientated, large hexagonal plates. The halo can be a near-circular bright spot, but it becomes more enlongated or oval in shape with increasing wobble and tilt of the plate crystals from the horizontal, or with a low-elevation Sun.

  Links in the image description will highlight features on the image. Mouse over the features for more detail.

  © George Anderson
  Derbyshire, United Kingdom of Great Britain and Northern Ireland
  Latitude: 53° 6' 0'' N
  Longitude: 1° 23' 24'' W
  16 April 2009 0730 (Local Time)
  
  
  Camera direction: towards E
  Image P/S code: P.13.1.7
  Image I.D.: 3810
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  Sub-horizon halos

  The high vantage point of a flight from Munich, Germany to Paris, France allowed this view of parhelia together with subparhelia and a subsun.

  The arc surrounding the Sun with a radius of 22° is the small halo. The small halo is one of the most frequently observed halo phenomena. On the right and left sides of the small halo, at the same elevation as the Sun, are bright coloured spots known as parhelia, or mock suns. Extending horizontally away from each parhelion are parts of the parhelic circle. The parhelic circle is a white circle that stands parallel to the horizon and passes through the Sun.

  Vertically below the Sun is the bright reflection halo that is the subsun, or undersun. The subsun is below the horizon and so is only seen from high vantage points, such as from aircraft or mountains. To the right and left of the subsun and vertically below the parhelia are corresponding subparhelia. Extending away from these are very faint parts of the subparhelic circle.

  Links in the image description will highlight features on the image. Mouse over the features for more detail.

  © Mark McCaughrean
  Germany
  Latitude: 48° 18' 36'' N
  Longitude: 9° 29' 24'' E
  24 October 2012 1642 (Local Time)
  
  
  Camera direction: towards WSW
  Image P/S code: S.13.1.1 7
  Image I.D.: 4128
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  Subsun

  This subsun, or undersun, was viewed from the summit of Mt. Wendelstein (1 838 m) in the Bavarian Alps, Germany.

  The subsun is a halo phenomenon produced by the direct reflection of sunlight on ice crystals in the cloud. A cold easterly airflow covered the area as a result of high pressure over northern Germany and low pressure between Corsica and Italy. The air temperature within the Stratocumulus cloud was around –17 °C.

  The phenomenon can only be viewed when looking downwards, and so is only observed from a high vantage point such as from aircraft or mountains.

  Links in the image description will highlight features on the image. Mouse over the features for more detail.

  © Claudia Hinz
  Mt. Wendelstein, Bavarian Alps, Germany
  Latitude: 47° 42' 10'' N
  Longitude: 12° 0' 44'' E
  11 February 2012 1615 (Local Time)
  
  
  Camera direction: towards WSW
  Image P/S code: S.13.1.7
  Image I.D.: 4129