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 | Vega is a "reference star", one of the brightest, it is classified as magnitude-0. Here is a series of photographs taken through a telescope operating at f/9.9 at a magnification of approximately 50. The ISO setting was 800. A 512x512 pixel section was obtained for each exposure which ranged from 30 seconds to 1/2000 sec. Here are the original images (to 1/1000) after converting to 16-bit linear tiffs.
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| It can be seen that there is some severe motion blur in several of the images. The longer exposures are subject to mirror shift and tracking errors, the short exposures to vibrations induced by the shutter action. The images were de-blurred by a modified Lucy-Richardson deconvolution (modified to handle the nonlinear saturation regions), and then manually aligned. Not all of the motion artifacts could be removed, an argument for better mechanical mounts and tracking. The shutter vibrations need to be solved in some other way. It is unusual to take sub-second shots of stars, but common for the moon and planets.
As can be seen below, the deblurring is only partially successful. The saturated regions are maintained but any signal "behind" it cannot be recovered. Still, this is an immense improvement for the purpose of adding these images together.
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Original image
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Conventional Lucy-Richardson deconvolution
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30 sec
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4 sec
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1/30, 2x spatial scale
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DeconvLucySat
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| The images were combined to form an HDR composite. Since Vega, and all stars for that matter, are essentially point sources, the result is a representation of the point spread function of the telescope's optics.
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