Re: Astro version of Canon 20D

From: matt (electro_optic_at_bellsouth.net)
Date: 02/15/05 

Date: Mon, 14 Feb 2005 20:43:17 -0500

Chris L Peterson wrote in message ...
>On Mon, 14 Feb 2005 18:25:30 -0500, "matt" <electro_optic@bellsouth.net>
>wrote:
>
>>not sure which IS Canon binos you're referring to . I opened a couple of
>>them and they have a moving lens not prism. One of the objective lenses
>>moves in some sort of yoke arrangement , with 2 degrees of freedom. Both
>>eyes are moved simultaneously by the same linear voice coil type actuator.
>>The control electronics have nothing to do with optics (no image motion
>>sensing per se) and derive their feedback signal from an Analog Devices
>>piezo accelerometer .
>
>I don't know if Canon uses different approaches, or if it has changed
>recently. A few years ago I examined a corrector that was essentially a
>variable prism- two flats with a flexible bellows between them, filled
>with oil, and driven by a pair of actuators. This is the type of
>mechanism I used for my tip/tilt corrector. The other approach would
>work too- it looks like what SBIG has adopted for its new large format
>tip/tilt device.
>
>_________________________________________________
>
>Chris L Peterson
>Cloudbait Observatory
>http://www.cloudbait.com

 the binos I opened were less than a year old and up to 50mm aperture . The
objective looked like an air spaced doublet in which the inner lens was able
to move sideways and up/down .
The piezo accelerometer was a dual axis chip , the ADXL variety .
Electronics looked simple.

Funny how SBIG and Starlightxpress decided to take a step backwards and made
the newer tip/tilt devices even slower than the AO-7, completely eliminating
any chance of correcting atmospheric turbulence . They should be called
integrated guiders not adaptive optics . I guess not only Meade is allowed
creative using of technical terms for the purpose of marketing .

best regards,
matt tudor

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