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EI2GYB > ASTRO 18.10.25 10:05l 93 Lines 5655 Bytes #23 (0) @ WW
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Subj: Mathematicians Are Making Earth Based Telescopes Rival Spac
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Mathematicians Are Making Earth Based Telescopes Rival Space Observatories
Ground-based telescopes have a fundamental problem that no amount of
engineering can fix. They're trying to observe the universe through Earth's
atmosphere, a constantly moving blanket of air that distorts and blurs incoming
light. It's a little like trying to take a photograph of the bottom of a stream
where the water is gently flowing! Space telescopes like Hubble easily sidestep
this issue by operating above the atmosphere, but they can only photograph tiny
slivers of sky. Now, researchers at Johns Hopkins University have developed a
clever mathematical solution that could give ground based telescopes near space
quality vision whilst retaining their ability to survey vast swathes of space!
Earth's atmosphere is never still. Temperature variations, changing pressure,
and other atmospheric conditions cause light from distant stars and galaxies to
refract differently as it passes through different layers. For bright objects,
this might create twinkling stars but for the fainter targets it creates a
significant problem. Traditional image processing techniques have struggled to
handle these distortions without either blurring important details or
introducing artificial graininess into the final image.
As a keen astronomical imager myself, the prospect is tantalising. With a whole
bunch of algorithms already at my finger tips to tweak and improve images, the
idea of a revolutionary new one is exciting. Called ImageMM, the new algorithm
uses sophisticated mathematical techniques to look through the atmospheric
turbulence and reconstruct what the sky actually looks like behind all that
interference. Tam s Budav ri, an astronomer and mathematician who led the
research, explains that sharpening our view doesn't just give us prettier
pictures. It allows telescopes to detect fainter, more distant objects and
pushes the boundaries of what's observable from Earth's surface.
ImageMM takes a different approach by modelling how light travels through the
constantly shifting atmospheric layers. Yashil Sukurdeep, the Johns Hopkins
mathematician who developed the algorithm, describes it as learning to see past
a restless sheer curtain to reveal the sharp, clear image hidden behind it. The
method relies on a mathematical technique called Majorization-Minimization,
adapted specifically for astronomical applications.
Early tests using data from the Subaru Telescope in Hawaii demonstrated the
algorithm's capabilities dramatically. The system processed blurry, noisy
images in mere seconds, revealing intricate details like the spiral structure
of distant galaxies with unprecedented clarity. What makes ImageMM particularly
valuable is its ability to handle the imperfections that plague real
observational data. Unlike existing tools, it effectively removes noise and
blur whilst dealing with missing pixel values that commonly occur during
observations. Sukurdeep notes that whilst astronomers will never have perfect
ground truth to compare against, this approach represents the closest thing to
a perfect reconstruction currently achievable.
The timing couldn't be better. The Rubin Observatory that has already started
collecting test data will later this year, begin to conduct extensive surveys
aimed at understanding dark energy and dark matter. For these studies,
accurately measuring the shapes of distant galaxies and detecting subtle
distortions caused by gravitational effects is crucial. Even small improvements
in image quality from billion dollar observatories translate to substantial
scientific gains.
It's fair to say that space telescopes excel at capturing deep, high-resolution
images, but they observe only tiny portions of the sky. Over 34 years, Hubble
has photographed roughly 0.1% of the observable sky. Ground-based facilities
like Rubin will image the entire visible sky every few days. With ImageMM
processing those hundreds of observations, astronomers may finally achieve
something close to space telescope quality whilst maintaining the comprehensive
sky coverage only ground based instruments can provide and, at a fraction of
the cost.
Source : Sharper than ever: New algorithm brings the stars into greater focus
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