From: "Bob May" 
To: "atmlist" 
Reply-To: "Bob May" 


Realtime tracking is rather easy with the sun as you have plenty of light
to do the work.  Take off a part of the image and have it go to a set of
photocells that are at the edge of the image.  You want to do a
differential reading on those two cells and position the sun so that it is
half on each of them.  You will also want to do another pair to set the
up/down of the image but that can be done once a day to make the sun
vertically near the center.  Dithering about will tend to happen if the
vertical is done all the time.
Rain sensors are not that hard to do.  The TASS people (Tom Droedge) has
already done up one for their MK IV telescopes and it seems to work well.
Things like resetting at the end of the day are easily accomplished by
hitting a stop and going back to the start point for the next morning and
so forth.  The computer can take care of opening the dome in the morning
and getting the sun on the sensors.  A feedback from the mirror and a
scanning of the sky will do the job very nicely . Bob May
http://nav.to/bobmay
bobmay{at}nethere.com
NEW! http://bobmay.astronomy.net

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