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Sundog in Antarctic conservation

Posted by Conservators Apr 2, 2012

Author: Georgina

Date: 28/03/12
Temperature: -23c
Wind Speed: 25 kts
Temp with wind chill: -38c
Sunrise: 8:39am
Sunset 7:15pm

 

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Sundog seen from Scott Base (photo by G. Evans, AHT)

 

For the past few weeks, we have been enjoying the rising and setting of the sun in something approaching normal daylight hours.  On Monday we were able to see a sundog, (scientific name: parhelion); a very special atmospheric phenomenon in which bright spots of light appear in the sky on either side of the sun.


Sundogs are created by ice crystals in the air which act as light-bending prisms. When randomly orientated, a complete halo or luminous ring around the sun is created, but at lower levels the crystals (sometimes called diamond dust) become vertically aligned, causing the light to be refracted horizontally.

 

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Detail (photo by G. Evans, AHT)

The spots we saw were like partial blurred rainbows, with the red side innermost. I didn’t get the chance to see one of these when I was last here in 2010, so I feel very lucky indeed to have seen one now.  Sundogs (also known as mock or phantom suns) can be seen anywhere in the world, but rarely as obvious or as bright as when the sun is low on the horizon and in very cold regions like Antarctica.

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Author: John

Date: 27 August 2011

Temperature: -11.2oC

Wind Speed: 22kts

Temp with wind chill: -19.7oC

Sunrise: 10.18am

Sunset: 3.35pm

 

 

The sun is getting closer to being visible at Scott Base.  It is actually above the horizon but still behind the hills and peaks of Ross Island.  There are some beautiful light effects and delicate colours to be seen in the sky.  Today there was a narrow, horizontal band of the palest pink in the South, across White and Black Islands, as the sun shone under the clouds in the North.

 

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The Sun Getting Closer!  John/AHT

 

While keeping a good look out for these beautiful effects, work and life at Scott Base must still go on.  Every Saturday at an All Staff Base Meeting, duties necessary for the smooth running of the Base are apportioned to all staff.

 

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Base Duties.  John/AHT

 

One such duty is the removal of snow and sea ice build up around Reverse Osmosis (RO) Intake/Outlet gantry at the ice transition.  Our team spent nearly two hours shovelling snow, cutting the sea ice with a chainsaw and removing these heavy blocks of ice.

 

The RO plant supplies all fresh water for the running of the base and provides two degrees of purity, RO1 for general use and a more pure RO2 for drinking, scientific projects, and work such as conservation of the Ross Island historic artefacts.

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Sun Dogs in Antarctic conservation

Posted by Conservators May 20, 2011

Posted by Jane, conservator with the Antarctic Heritage Trust

 

Date: 19th May 2011
Temperature: -19°C
Wind Speed: 20 knots
Temp with wind chill: -40°C
Sunrise:
Sunset


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Sun Dog between Mount Erebus and Mount Terror © AHT/Jane


We were treated to a rare sight just before the sun left us a few weeks ago. A really spectacular sun dog was visible when the sun was low beside Mount Erebus. Sun dogs are seen as a ring of light or halo around the sun with bright spots on either side. They are often seen in Antarctica when small ice crystals are blown up into the air. As they fall towards the ground, they align vertically and act as prisms which defract the light creating the effect. It is a really spectacular sight which we will unfortunately not see again for some time!

 

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Bright spot from the side of the sundog in front of Mount Erebus © AHT/Jane