[Laser] Big adaptive optics

Mon Sep 24 15:27:44 EDT 2007

Sorry if I misled anyone but I don't believe I mentioned adaptive optics in
connnection with this program.  It's SOFTWARE ONLY!

Although most people just wait for a good frame of video and stack it with
another, it's possible with the proper configuration and plugins to take
bits and pieces of frames and paste them together to reduce or eliminate
atmospheric distortion.  It takes a bit longer than adaptive optics but it's
also a LOT cheaper.  It's also possible to use a star near the desired
object and use it to steer the program to properly register the frames.
I've seen this done both with a natural star and with an artificial star
generated by laser but in this case the entire frame was either used or
thrown away and not pieced together.

None of this may be of much use when it comes to communications though as
the objective of this program is an actual image rather than just detecting
light.  Those with just a little bit of imagination have found very creative
ways to use simple programs like this and that's why I mentioned it for
those that may not be aware this program exists.  There's a LOT more to this
program than what appears on the surface.  I thought someone might be
interested in the program and exploring it's possibilities in ways that may
not be apparent upon first examination.  I appologize if you found my post
offensive or misleading.  It would have been VERY helpful if the originator
of this topic posted a link to the article in question.  That way I'd have a
better understanding of what was being discussed.  I looked for a link but
didn't find it.  Perhaps I missed it?

=====

----- Original Message -----
From: "Terry Morris W5TDM" <w5tdm at hotmail.com>
To: <laser at mailman.qth.net>
Sent: Saturday, September 22, 2007 1:17 AM
Subject: Re: [Laser] Big adaptive optics

> Astrovideo is not adaptive optics. It is just an image accumulator, just
> collects a lot of images and then throws away the bad ones, and adds the
> good ones. It does nothing to correct the wavefront in real time. For
laser
> communications it would be of no use. Adaptive optics has some active
> optical element that moves to correct out of phase wavefronts. There are
> some adaptive optics avaliable for the amateur astronomer. Made by Santa
> Barbara Instrument group, called the AO-8 and AO-L. The AO-8 is set for a
> target price of under $600, but that doesn't include the CCD camera which
is
> not cheap. The CCD camera has two CCD sensors, one big for imaging, and a
> small one for tracking. The adaptive optics use the small CCD detector to
> detect the wavefront and drive the feedback loop to correct the out of
phase
> image.
>
>
> >From: "Laser @ KatHouse1.com" <laser at kathouse1.com>
> >Reply-To: Free Space LASER Communications <laser at mailman.qth.net>
> >To: "Free Space LASER Communications" <laser at mailman.qth.net>
> >Subject: Re: [Laser] Big adaptive optics
> >Date: Fri, 21 Sep 2007 15:35:15 -0400
> >
> >This has also been available to the backyard astronomer for quite a few
> >years using a standard video camera and a program called Astrovideo.
I've
> >been using the program for quite a few years.  The results are nothing
> >short
> >of spectacular not only for eliminating atmospheric distortion but also
> >because it has the ability to stack images and literally pull the image
up
> >out of the noise.  I can see objects using this setup that I can't even
> >begin to see using my eyes and any eyepiece that I own  I can image deep
> >space objects from my light polluted front yard by lining the camera up
on
> >the known starfield around the desired object then let Astrovideo do it's
> >magic.  Sometimes in as little as 10 to 15 seconds the desired object
will
> >start to appear out of the noise.  The program has many different modes
> >depending on whether you are trying to enhance signal to noise, eliminate
> >atmospheric distortion or both.  The program has both automatic and
manual
> >modes for stacking images.
> >
> >http://www.coaa.co.uk/astrovideo.htm
> >
> >=====
> >
> >----- Original Message -----
> >From: "J Forster" <jfor at quik.com>
> >To: "Free Space LASER Communications" <laser at mailman.qth.net>
> >Sent: Wednesday, September 19, 2007 1:52 PM
> >Subject: Re: [Laser] Big adaptive optics
> >
> >
> > > This idea has been around on that telescope since at least the 1960s.
It
> >was first done with movie film as I remember.
> > >
> > > -John
> > >
> > >
> > >
> > > James Whitfield wrote:
> > >
> > > > I just read an article that was forwarded to me by members of the
> >astronomy club about a technique for using adaptive optics on the 200
inch
> >Hale telescope on Mount Palomar.  The concept is that the dynamics of the
> >atmosphere will cause for brief times on small areas of the image formed
by
> >the telescope to have less blurring than the image as a whole or if the
> >pixels are integrated for longer times.  The use of a "fast" ( all of 20
> >frames per second ) camera is used to capture a succession of images
which
> >are then searched for these "lucky" patches which are then combined.  I
> >thought it was interesting reading.  (  If you are curious, try searching
> >for "Palomar" and "Lucky Camera". )
> > > >
> > > > There might be something that can be adapted to light communication
> >experiments at our level.  Maybe use the peak output from an array of 16
> >light sensors.  Maybe integrate the light comming to a sensor during a
> >frame
> >then reseting it.  Maybe it is just thinking about the optical system for
> >an
> >image telescope as it contrasts to a communications instrument ( What
does
> >sharp focus/blurred image mean for a single pixel camera?  Or light
> >modulated with a data stream? ).
> > > >
> > > > Does it spark any ideas for any of you?
> > > >
> > > > James
> > > >  n5gui
> > > >
> > >
> > > _______________________________________________
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> > > Laser at mailman.qth.net
> > > http://mailman.qth.net/mailman/listinfo/laser
> >
> >
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