Re: How to computurize (auto point+track+focus) BT252 Dobsonian telescope ?


"Roska Gozwild" <rg@xxxxxxx> wrote in message
news:43071d3b$0$25808$afc38c87@xxxxxxxxxxxxxxxxxxxxxxx
> How to computurize (auto point+track+focus) 250 mm Dobsonian telescope
> of type as shown in the following link
> (http://www.bintel.com.au/BT252.html) ?
> Is there any motorized "GOTO" unit suitable for BT252?
> Any suggestion?
The cruel answer is "you can't"....
However being slightly less negative, it depends what you really want to
do?. For imaging, the answer is a 'barn door' tracker. This is a base,
upon which you stand the whole scope, which tracks the sky movement, for a
limited period to give a photo capability. The advantage of this, is that
it cures field rotation, which will otherwise apply to any tracking
solution on the alt/az mount. For 'finding' things, you might be able to
modify the Orion 'push to' system, if you can get the parts, and there
have been a couple of similar 'locators' marketted in the past. Possibly
the closest to a full Goto you will find, will be the 'Dob tracker', at:
http://homepages.accnorwalk.com/tddi/tech2000/page3.html
With this and a really old 'scrap' laptop, will give you a pretty
competent tracking/Goto system. The Mel Bartel's drive program can also be
used in a similar way.
The problem though is that the total cost, may well exceed that of an 'off
the shelf' Goto scope...
Focussing will not be done by this system. Automatic focussing would
require a CCD imager, and be vastly more expensive. For a focus motor
(which was the advantage of allowing you to focus without touching the
scope), you could either adapt a RoboFocus to fit (which is great if you
are thinking about trying to image), or fit almost any simple DC 'model'
motor with a gearbox, and a couple of push buttons. The latter is
reasonably cheap to do, while the former is good, but costly. You could
also use one of the simple stepper motor drive programs to do the same.

best Wishes



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