
Adaptive Optics, a rapidly-evolving technology in astronomy - dnetesn
http://alliance.nautil.us/article/199/opening-a-new-window-into-the-universe
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brunosan
I'm surprised there's no mention to adaptive optics in solar physics. It's
essentially the same, but some interesting differences. Since there's more
light you can have more corrections per second, better approaching the
assumption of constant deformación during between corrections on a small view
angle ("constant isoplanatic patch"). Also there's no "perfect star" to
correct to, so calculation run on a closed loop to basically improve contrast
of the reference. The needed correction is also bigger during the day, since
the atmosphere is more turbulent. In the last few years there also have been
really cool improvements to account for different layers of the atmosphere and
better faster algorithms to correct wider and wider fields of view. This is an
example (from my PhD) of the state of the art 9 years ago, but illustrates the
huge difference: [https://youtu.be/x3JkjXco6m0](https://youtu.be/x3JkjXco6m0)

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abecedarius
This article is very light on details about the proposed next-gen adaptive
optics system. If you already know what that means, the only new info I could
glean was that they mean to use seven laser spots ("guide stars") instead of
one.

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cmehdy
That's what it looks like. Having more lasers and more processing power could
very well help with estimation of atmospheric disturbance (although I don't
know of any model being computationally overwhelming, but my knowledge is
limited), while better actuators on the mirrors would allow a more accurate
correction of the wavefront (as fast as possible ideally). Sounds like a mix
of HW upgrade and more inputs for estimation.

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bfe
The author, Andrea Ghez, is one of the leading researchers on observing the
center of our galaxy, and the stars that orbit the central black hole, among
other things.

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kirrim
Sounds like a Shack-Hartmann wavefront sensor, just being measured many times
throughout the exposure:
[https://en.wikipedia.org/wiki/Shack–Hartmann_wavefront_senso...](https://en.wikipedia.org/wiki/Shack–Hartmann_wavefront_sensor)

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perilunar
> there is really no substitute for the light-gathering power of telescopes
> too huge to be put into space.

Why is there any limit to the size of telescopes we can put in space? The
mirrors are segmented anyway - just stack 'em on top of a couple of rockets
and assemble in orbit.

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madengr
So, unlike radio astronomy, it's not feasible yet to have multiple, smaller
coherent telescopes? A phased array with magnitude and phase correction being
applied to each telescope.

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nullc
There are optical telescopes that use interferometry
[https://en.wikipedia.org/wiki/Astronomical_optical_interfero...](https://en.wikipedia.org/wiki/Astronomical_optical_interferometry)

But given the we don't have multi-THZ digital sampling, I guess, all the work
has to be done in the analog domain in realtime... which is pretty limiting
compared to what is possible with radio.

