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Narrow
band images.
Amongst the nebulae regions are those areas that are predominantly Emission nebulae. The atoms in the clouds of high temperature gas are energized by ultraviolet light from a nearby star and emit radiation as they fall back to lower energy states (in much the same way as a neon light). Other types of nebulae also emit specific wavelengths of energy based on the elements and mechanisms present in their structure. Narrow band images use special filters that pass specific wavelengths of light. These wavelengths are chosen to match the energy emitted by elements present in the nebulae. The list below gives some of the predominant elements and their emitting wavelengths.
The most predominant of these elements is Hydrogen
making the wavelengths of H Alpha and H Beta very important. The triple
ionised Oxygen (OIII) and double ionised Sulphur (SII) are also important.
The seperate images taken through the different filters can then be
combined into colour images. Because narrow band filters isolate specific
wavelengths it is possible to use them under light polluted and Moonlight
skies where conventional imaging would be difficult or impossible.
This page contains those images that I believe represent
my best efforts to date. If you disagree, or think others should be
there instead, let me know.
This page contains images of phenomena, objects and
events that do not fall neatly into one of the main heading catagories.
You will find pictures of aurora, sunsets and such like here.
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I have been interested in Astronomy for many years but did not get my first telescope until 2000. My interest soon turn to astrophotography, inspired by the many excellent images from across the world in magazines, and on the web. I do most of my imaging from my garden in Wiltshire, UK with the occasional trip to darker sites. I am fortunate enough to live on the edge of Salisbury Plain so do not suffer from as much light pollution as many areas in the UK. However, I still have to cope with some pollution to the south and east where I look out over the towns and villages. I begin taking images with 35mm black and white film that I processed in my own dark room. I then progressed to CCD imaging, where I have made the most significant progress as my experience has increased. This site contains most of my images, from the earliest, to my latest. Needless to say the quality has improved. It is hoped that by showing the good alongside the bad, others will be encouraged to keep at it. Finally I would like to thank all those other astrophotographers out there who have shared their experience so that others like myself can progress. Some images on this site were created with the help of the ESA/ESO/NASA Photoshop FITS Liberator. All images on this site are the property
of David Osborne unless otherwise stated.Please let me know if you wish
to use any of these images. |
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