METROPOLITAN SKIES
By Dave Trapani
SkyRunner
S
ky
Conditions
Aurora Borealis
The origin of the aurora is 93 million miles from Earth at the Sun. Energetic particles
from the Sun are carried out into space along with the ever present hot solar wind.
This wind sweeps supersonically toward Earth through interplanetary space at
magnetic field. The solar wind distorts the Earth's magnetic field to create the
comet-shaped , plasma-filled magnetosphere. The terrestrial magnetic shield acts as
a barrier, protecting the Earth from energetic particles and radiation in the hot solar
wind. Most of these energetic particles are deflected around the Earth by the
magnetosphere, but some get trapped. Electrons trapped in the Earth's magnetic field
(the magnetic mirror effect) are accelerated along the magnetic field toward the polar
regions and then strike the atmosphere to form the aurora. Auroras are most
intense at times of intense magnetic storms caused by sunspot activity. The
distribution of auroral intensity with altitude shows a pronounced maximum near
100 km above the Earth.

The particles, which stream down the magnetic field of the Earth, reach the neutral
atmosphere in a rough circle called the auroral oval. This circle, or annulus, is
centered over the magnetic pole and is around 3000 km in diameter during quiet
times. The annulus grows larger when the magnetosphere is disturbed. The location
of the auroral oval is generally found between 60 and 70 degrees north and south
latitude. During intense solar activity, the auroral oval expands, and aurorae have
been seen from latitudes as low as 25-30 degrees north and south on extreme
occasions. For example, on November 7, 2004, following a Coronal Mass Ejection,
they were seen as far south as Arizona. At 45 degrees, aurorae are visible
approximately five times per year, while above 55 they are visible almost nightly.
Aurora From My Deck - 11.07.04

Image Capture Details

Optics:  Zeiss Lens on Sony 717F Camera
Mount: Meade
Camera: Sony 717F
Filters: None
Time:
Exposure:  30 Seconds
Location: Waldwick, NJ
I walked out onto the deck one
night, saw this and grabbed the
camera.  I never saw the
Northern Lights from NJ before.  
What a great site!
Click for larger image
Aurora From My Deck - 11.07.04

Image Capture Details

Optics:  Zeiss Lens on Sony 717F Camera
Mount: Meade
Camera: Sony 717F
Filters: None
Time:
Exposure:  30 Seconds
Location: Waldwick, NJ
Click for larger image

Image Capture Details

Optics:  Zeiss Lens on Sony 717F Camera
Mount: Meade
Camera: Sony 717F
Filters: None
Time:
Exposure:  30 Seconds
Location: Waldwick, NJ
Click for larger image
Aurora From My Deck - 11.07.04

Image Capture Details

Optics:  Zeiss Lens on Sony 717F Camera
Mount: Meade
Camera: Sony 717F
Filters: None
Time:
Exposure:  30 Seconds
Location: Waldwick, NJ
In the very top of the image you
can see the star cluster - The
Pleiades (The Seven Sisters).
Click for larger image
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