From: albe albo <richter1956@yahoo.com>

Date: April 26, 2010 9:12:44 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: [Astro_IIDC] Encoder  self-correction question....

Hello to all.

I just saw the "real" device that I figured out in my mind since long time ago  

The principle is very simple and i guess that many people thought to it: a encoder that reads the AR axis rotation detecting any error ( periodic or not)  in real time allowing a real time correction.

A kind of autoguide without stars.

Some years ago,when  i thought to such device i was answered that such encoder was a dream and that it didn't exist but now i see that someone did such corrector.

The interesting fact is that changing the mechanical adapter will allow to transport the device on different mounts.

Someone have feedback about it?

http://www.mda-telescoop.com/index.php?option=com_content&task=view&id=52&Itemid=82

Now i was thinking to a Mac - Astro IIDC software based version of such device simply buying an encoder (i found one with 3,6 arcsec resolution) and attaching it directly to the AR axis.

I was thinking that even a  resolution > of 1 arcsec could be used because the software could read the "trend"  and correct it.

http://www.microesys.com/drcEncoders/pdfDRC/Model%20M35%20Data%20Sheet.pdf

The question for Milton: is such kind of correction so different from an autoguiding?

Which kind of conversion is needed between the phisical encoder and the USB port in order to simulate the data that AstroIIDC get from the guide star?

That device send its control pulse trough the ST4 port like a normal autoguide.

It could be interesting to do some experiments (even with rougher encoders) in order to understand the feasibility.

Thank you for the attention

Alberto