Adaptive Optics for large amateur telescopes

I don't know of any commercially available AO systems for amateur
telescopes. Do you? (I'm not including the tip/tilt correctors available
from some camera manufacturers.)

How do the SBIG adapters work?
--
Curtis Croulet
Temecula, California

Dear John,


When you start losing a battle, you devise ways to either get around further
battle or win it. *Since amateurs, even in larger numbers, can't fight
against industrial progression (ie increasing light to compensate), they
have devised ways to work around it. *CCD/ filters have opened doorways that
would have been nearly impossible, even in darker skies.

The problem is that the vast majority of amateur (and professional
too) astronomers did not even start the battle!
In Italy very few people (a few dozens at most) STOPPED the increase
of the artificial sky brightness in our most developed regions since
2000, while in the years before there was a twofold increase each
decade!
In Italy amateur astronomers are in the order of about 20000...

"Chris L Peterson" wrote in message

Let me get this straight, are you saying that adaptive optics are designed
to counteract jetstream effects?

I'm saying that the kind of distortions introduced by upper level winds
are the sort that higher order correctors can compensate for.

I really can't see how that's possible. If you have, say, a constant upper
level wind of 100 Km/h that completely smears the image, making it totally
blurry, how is AO going to compensate for that? Now if the winds are much
slower ("slow" seeing) and the object boils but is clear at times, I can see
how such a system would help. In fact, that's where webcams are often used
for this type of seeing.

If so, I have yet to see any amateurs
image planets with outstanding results using an adaptive optics system
with
poor jetstream type seeing. If you know of a site where this has been
done,
I'd like to see it.

I've used an 8-zone deformable mirror to visually improve the
performance of a 12" scope (3*r0) on Jupiter, Saturn, and Mars. The
imaging results were poorer than you can easily get with a video camera
and lucky imaging. We gave up on this project a few years ago because it
didn't seem very useful, and didn't have any commercial value.

That's why I'm questioning what you're saying about the type of seeing AO
handles. If slow seeing, yes, but no way if the image never deblurs due to
high jetstream winds.

I don't know of any commercially available AO systems for amateur
telescopes. Do you? (I'm not including the tip/tilt correctors available
from some camera manufacturers.)

Probably because they won't work for the kinds of seeing often encountered
over the US.

JW
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On Wed, 24 Jun 2009 21:01:36 GMT, "Curtis Croulet"
wrote:

How do the SBIG adapters work?

They are tip tilt. The older system pivots a mirror, the newer shifts a
lens. They can compensate for zero order distortion up to about 10 Hz.
This is of limited value for correcting seeing, since even for zero
order the isoplanatic region is much smaller than the typical camera
FOV, not to mention that the star used for feedback is itself off the
main frame. Mostly these AO units are correcting for mount tracking
errors.
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On Wed, 24 Jun 2009 17:13:38 -0400, "John Walsh"
wrote:

I really can't see how that's possible. If you have, say, a constant upper
level wind of 100 Km/h that completely smears the image, making it totally
blurry, how is AO going to compensate for that?

That's not what a constant upper level wind does. In fact, such a wind
by itself would cause no distortion at all. The problem comes from
turbulence, which results in volumes with different densities blowing
through the telescope field. Those moving zones produce focus and
astigmatism errors, which are normally the first level of correction
after tip/tilt. Their effects travel across the focal plane at speeds
that are typically able to be tracked by deformable mirrors.

Fast and slow seeing are not generally differentiated by the speed of
the upper level winds.

Probably because they won't work for the kinds of seeing often encountered
over the US.

Well, I know from personal experience that they work right under the
U.S. jet stream. It's just that their use is so limited (visual
observation of a few bright planets... not even the Moon or Sun) that
nobody is likely to be interested in investing in a product.
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Well, I know from personal experience that they work right under the
U.S. jet stream. It's just that their use is so limited (visual
observation of a few bright planets... not even the Moon or Sun) that
nobody is likely to be interested in investing in a product.

I think that once a reliable prototype that allows you to see 'only'
Jupiter, Saturn and Mars almost like the HST (but WITH YOUR RETINA)
will be shown at Texas Star Party or Winter Star Party it will be an
instant success. Of course it will also depend on its cost, but I'm
sure that there will be a market for it.
Fabio Falchi

On Jun 24, 10:32*am, Chris L Peterson wrote:

AO does not work for large FOV systems, which is why there can be no
market for most imagers.

Chris L Peterson
Cloudbait Observatoryhttp://www.cloudbait.com

For the present implementations that is true. However, conceptually
it could be made to work by using two AOs on opposite sides of the
aperture stop. For relatively small aberration correction (which is
generally true) the combination could considerably extend the FOV. I
would expect there to be some ongoing design / research in this
direction.

www.richardfisher.com

CieloBuio wrote:
Well, I know from personal experience that they work right under the
U.S. jet stream. It's just that their use is so limited (visual
observation of a few bright planets... not even the Moon or Sun) that
nobody is likely to be interested in investing in a product.

I think that once a reliable prototype that allows you to see 'only'
Jupiter, Saturn and Mars almost like the HST (but WITH YOUR RETINA)
will be shown at Texas Star Party or Winter Star Party it will be an
instant success. Of course it will also depend on its cost, but I'm
sure that there will be a market for it.

A handful of keen planetary observers with very deep pockets might buy
it but it would likely need a 0.5m or larger scope for the light grasp
determining rapid corrections in multimode operation.

Comparatively few amateurs have 1m class scopes.

Regards,
Martin Brown

A handful of keen planetary observers with very deep pockets might buy
it but it would likely need a 0.5m or larger scope for the light grasp
determining rapid corrections in multimode operation.

Comparatively few amateurs have 1m class scopes.


Yes, but there are a 'lot' of 60 to 80 cm out there. And their owners
will be happy to use them at their full potential on the three cited
planets.
Let's start showing a working AO system at a major star party and
everyone will want the new toy.

Best,
Fabio Falchi
www.cielobuio.org
www.istil.eu

On Jun 26, 12:10*pm, CieloBuio wrote:

Yes, but there are a 'lot' of 60 to 80 cm out there. And their owners
will be happy to use them at their full potential on the three cited
planets.
Let's start showing a working AO system at a major star party and
everyone will want the new toy.

Maybe. A "stacking" electronic eyepiece would probably be cheaper and
provide better "live" images though. Get an ARM7 (or an Atom), a few
gigabytes of NAND flash, score images in real time and align and
stack, for example, the best 100 frames of the last minute.