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photo:aurora

observing and photographing aurora borrealis and aurora australis

introduction

  • a prominent aurora display can be an awesome visual event in dark skies and makes a great photographic subject.
  • unfortunately, to see them one must be in the right place at the right time with clear skies
  • the chance of seeing one depends upon:
    • the strength of the storm - this is measured by its Kp value (0-9 with 9 being the max)
    • your latitude
    • clear skies away from light pollution
  • that usually means the far northern hemisphere at latitudes around the +60deg region or in the south (-50 to 60deg latitude)
    • with extreme magnetic storms, brief events may be visible from southern parts of Australia but they are no where near as dramatic as at higher latitudes, so if you want the best displays, one must go in winter or preferably around the times of the equinoxes (eg. Sept or March) to very cold places such as Iceland, Scaninavia, Alaska or Canada (summer is no good at such latitudes as the long summer twilight interferes with visibility)
  • best quality images usually require a modern full frame dSLR with manual focus and magnified Live View, 24mm f/1.4 lens or Zeiss ZE 21mm f2.8 if you need wider, tripod and you may still need ISO 1600. If your lens is not great in the corners wide open, you may need to stop down to f/2.8.
  • aurora displays can be very short-lived lasting only 10-20 minutes so you must be well prepared

solar storms

solar particle storms

  • stars similar to the Sun produce a gigantic outburst of radiation on average about once every hundred years per star. Such superflares release more energy than a trillion hydrogen bombs and make all previously recorded solar flares pale in comparison. “It is unclear whether gigantic flares are always accompanied by coronal mass ejections and what is the relationship between superflares and extreme solar particle events.” 1)
  • solar particle storms are rare, but when they occur, they bombard Earth with an enormous amount of high-energy particles.
  • solar particle storms can greatly enhance the normal production of cosmogenic isotopes like radiocarbon (14C) in the atmosphere by galactic cosmic rays. These can be detected as Miyake events in tree rings
  • 12350BC: strongest solar event ever detected - 18% stronger than the notorious AD 775 event and over 500 times more intense than the 2005 storm
  • other large known solar particle storms have occurred around 994 AD, 663 BC, 5259 BC and 7176 BC

solar electromagnetic storms from solar flares

  • these are the relatively common events which cause aurorae to appear on earth
  • the famous Carrington event in 1859 was not accompanied by a solar particle storm and only had ~1% of the energy of a superflare, but the telegraph network collapsed in large parts of northern Europe and North America.

Aurora Borrealis

  • the “Northern Lights”

For some awesome photographs:

Aurora Australis

In Victoria, you need a Kp of 8-9 to have any chance of seeing one:

www.aurora-service.net_wp-content_uploads_2013_08_aurora-australis-kp-map.jpg

image courtesy of http://www.aurora-service.net/aurora-forecast/

It is seen best from Antarctica such as this one from Mawson base in 2003.

In an extreme event, the aurora australis may be seen as far north as -35deg latitude, such as this image by Adam Marsh taken in Tocumwal, NSW, Australia in March 2012 at ISO 1600, f/3.5 and 30sec exposure:

i919.photobucket.com_albums_ad32_blacklegend17_astronomy_20and_20related_aurora_20-_20tocumwal_20-_202012-03-12_img_3256er.jpg

10 minutes of this approx. 20 minute event on March 12th 2012 was captured and animated by Michael Mattiazzo in Castlemaine, Victoria using 25 frames of 15 sec exposures at ISO 800 using an 18mm focal length on a Canon 300D:

photo/aurora.txt · Last modified: 2025/05/16 10:29 by gary1

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