#adaptive optics

To the naked eye, stars twinkle, they do so not because the stars are massively variable in their light output (although some are variable, for a different reason), but because the atmosphere between us and space acts like an image does through moving water, it distorts, it shimmers and keeps changing.

For centuries since optics were invented this has been a limiting factor, very distant objects just smudge about too much to be really able to see them clearly.

In the 1950s and later in Sci Fi books of the 70s, the idea of adaptive optics took place, a counter balance to the ever changing flow of air, to be able to smooth out the distortion. It wasn't until the 1990s that such systems really came online, and improved our image of the universe, however by then the Hubble Telescope had already got above the atmosphere to make even the small enhancements of the ground based brethren limited.

Now, with several space based telescopes, a new method has been designed, one that is proving to be far superior to the older adaptive methods.

A team of US/China based scientists are using AI and deep learning to compare Hubble and ground based telescope images, and teach the AI how to compensate for the atmospheric turbulence. Comparisons have shown a 38% improvement compared to 7% from existing AO based solutions.

Space based Telescopes are the future, but ground based telescopes have many other kinds of advantages, particularly in terms of maintenance, upgrade and access. More so, not every bit of science done requires the access of the sharpest possible image, one such project aims to simply record widest possible image of the night sky over a period of time, so rather than 100 telescopes all peering at pin-pricks of the sky, these ground based telescopes scan huge areas of the sky and record it, looking for any changes.

There's a good reason nobody walks around with binoculars stuck to their faces, you may see more in the visible area, but miss the obvious sat next door.

Source :

A Giant Leap Towards Defeating Astronomy’s Greatest Enemy: Earth’s Atmosphere

“Even at high altitudes, with smooth, dry air and cloudless skies, atmospheric distortion is severely limiting. That’s where the science of Adaptive Optics comes in. A portion of any incoming light is immediately analyzed for identifiable distortions of known, point-like sources. Algorithms compute the shape of a mirror required to “undistort” that light. A secondary mirror “adapts” its shape to counteract atmospheric distortion. This clever scheme creates a crisp image that can surpass even Hubble’s capabilities.”

If you want to defeat Earth’s atmosphere, you just go to space, right? Except going to space is more expensive, riskier, much more difficult (if not impossible) to upgrade, and places a limit on the size of your telescope. From the ground, telescopes can be cheaper, larger, easier to upgrade, and don’t have any risk of a launch failure. But, on the other hand, they still have to contend with Earth’s atmosphere, which is a bit like trying to see the Universe from the bottom of a swimming pool.

Zoom a little closer

I’ve featured the Carina Nebula before on zespaceblog, but this image taken from Earth based telescopes and sharpened by using adaptive optics, a process of removing the wobble of Earths atmosphere (responsible for the twinkling of the stars in our sky) by counter movements on mirrors in the telescope.

The nebula is available to zoom in and out of here :-

This Is How Astronomy Is Finally Defeating Its Greatest Enemy: Earth's Atmosphere

“This is not only a tremendous boon to astronomy, but represents the potential of successful collaborations between government-funded endeavors and private industry. Without the participation of both, improvements such as these would have been impossible. With 25-to-39 meter class telescopes scheduled to come online in the coming decade, including the future ELT at 39 meters and also managed by ESO, it's never been a better time to be a ground-based astronomer. 

For decades, the only ways to contend with the atmosphere were either to live with it or to go above it. Yet over the past few years, all of that is changing. It's time to seriously consider outfitting all of our large observatories with adaptive optics systems like this. If these improvements continue, ground-based astronomy may be able to surpass space-based telescopes, as far as quality-imaging-per-dollar goes, once and for all!”

So, you want to view the Universe as accurately as possible, but you don’t have the ability to put your dream observatory in space? Welcome to the world of astronomy, where there’s a trade-off between what you can do from the ground (where weight and size are no concern) and what you can do from space (where you don’t have an atmosphere). The Hubble Space Telescope has been so revolutionary because of all that it could see without any atmospheric interference, but the ground is catching up. The science of adaptive optics is progressing tremendously as the years go by, enabling us to compensate for the atmosphere and. in some cases, to even defeat Hubble with telescopes here on Earth.

How light became language, and images learned to think. The Hook, Before You Ever Looked at a Screen Before cameras.Before lenses.Before pixels. You were already inside an imaging system. Your eyes. Photons entered.Neurons fired.Meaning emerged. Every act of seeing has always been an experiment. Modern optics and imaging didn’t invent vision. They questioned it Ancient Light: When Seeing…