Stella Imaging
January 29th 2008 08:12
Previously images from ground-based telescopes have been invariably blurred by Earth's turbulent atmosphere. Therefore ground based telescopes produced images that often contained aberrations and distortions caused by the Earth’s ever changing atmospheric conditions.
Having a telescope orbiting space above the Earth’s atmosphere was the optimum choice because it offered images with greater resolution and image definition.
Astronomers needed a way of improving images gathered by earth based telescopes, necessity being the mother of invention newer imaging techniques need to be developed.
A new technique, known as adaptive optics (AO), to correct the blurring was developed before this technique cameras mounted on telescopes where usually large format film plates which needed to be manually developed with only one image being taken at a time. With the advent of the new (charged coupled device) CCD chip came digital photography a new noise-free, high-speed camera has since been developed for the express purpose of taking multiple digital images at a time.
The camera works by recording partially corrected adaptive optics images at high speed (20 frames per second or more). Software then checks each image to sort out which are the clearest and sharpest. Although many images are still significantly smeared by the atmosphere, a small percentage of them are unaffected. The software uses these unaffected images and produces a composite image. The technique is also called "Lucky Imaging" aptly named because it depends on the chance fluctuations in the earth’s atmosphere.
Astronomers were able to obtain images that are twice as sharp as those produced by the Hubble Space Telescope a remarkable achievement indeed. Astronomers also observed very fine detail in objects such as the Cat's Eye Nebula (NGC 6543). It is eight times closer to earth than M13, allowing filaments that are only a few light-hours across to be resolved.
With the relative low cost of digital cameras and available software on the market even amateurs can achieve clear images of stars and planets.
This image of Mars and Orion was taken outside my back yard using a Nikon D80 Ap 5.8 Exp: 30 seconds ASA 1600 : lense 135mm.
A view of the Cat's Eye Nebula NGC 6543 inhanced image underneath
Astronomers needed a way of improving images gathered by earth based telescopes, necessity being the mother of invention newer imaging techniques need to be developed.
A new technique, known as adaptive optics (AO), to correct the blurring was developed before this technique cameras mounted on telescopes where usually large format film plates which needed to be manually developed with only one image being taken at a time. With the advent of the new (charged coupled device) CCD chip came digital photography a new noise-free, high-speed camera has since been developed for the express purpose of taking multiple digital images at a time.
The camera works by recording partially corrected adaptive optics images at high speed (20 frames per second or more). Software then checks each image to sort out which are the clearest and sharpest. Although many images are still significantly smeared by the atmosphere, a small percentage of them are unaffected. The software uses these unaffected images and produces a composite image. The technique is also called "Lucky Imaging" aptly named because it depends on the chance fluctuations in the earth’s atmosphere.
Astronomers were able to obtain images that are twice as sharp as those produced by the Hubble Space Telescope a remarkable achievement indeed. Astronomers also observed very fine detail in objects such as the Cat's Eye Nebula (NGC 6543). It is eight times closer to earth than M13, allowing filaments that are only a few light-hours across to be resolved.
With the relative low cost of digital cameras and available software on the market even amateurs can achieve clear images of stars and planets.
Orion and Mars seen on the lower portion of image
This image of Mars and Orion was taken outside my back yard using a Nikon D80 Ap 5.8 Exp: 30 seconds ASA 1600 : lense 135mm.
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