[Laser] Big adaptive optics

[Terry Morris W5TDM]

>From: J Forster <jfor at quik.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: Sat, 22 Sep 2007 11:23:21 -0400
>
>Terry Morris W5TDM wrote:
>
> > 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.
>
>Do you know if the SBIG unit is just a tip-tilt tracker or does higher 
>order
>corrections? With a smallish aperture 'scope, say less than 24", tip-tilt 
>and frame
>selection might produce some very good imagery.
>
>-John


Yes, it is just a tip-tilt optical element, so no moving reflective arrays, 
so no high order corrections. The example images do seem to show much 
improvement. Unsure how much this would help in laser communications, but 
would seem to reduce beam wobble on the detector. If you know who SBIG is 
you may have already seen this, but just in case here are links:

http://www.sbig.com/sbwhtmls/ao8.htm

http://www.sbig.com/sbwhtmls/online.htm

The second link shows the internal working parts of the AO-L

-Terry w5tdm

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