Re: [APML] Computerized Barndoor Tracker

[George Anderson <georgea@cam.org>]

The curved rod barn door tracker eliminates the need to correct for
tangential drive errors. The main difference is that the nut is driven
and not the rod. Drive accuracy is then limited by the quality of the
curve in the rod and machining errors.

George Anderson
Montreal Canada

Clear skies and good health

> Scott Hammonds wrote:
> 
> Mike,
> There are also a couple of designs that allow for longer exposures and
> take into consideration the changing angle of the bolt. Do a Google
> search on Barn Door Trackers and you should be able to find what you
> need. I believe the best design is a type 4 double arm tracker that
> will allow up to 30-45 minutes without any appreciable error. Good
> luck,
> 
> Scott Hammonds
> 
> 
> ----------------------------------------------------------------------
> From: astro-photo-bounces@seds.org
> [mailto:astro-photo-bounces@seds.org] On Behalf Of Chris Schur
> Sent: Wednesday, March 31, 2004 7:33 AM
> To: Discussion of Film Astrophotography
> Subject: RE: [APML] Computerized Barndoor Tracker
> 
> Mike, you wont need a laptop to drive a barn door traker, just a
> microcontroller.  the math is fairly simple, when the boards are
> paralell, a radius of 11.46 inches a 1/4 -20 bolt drives 1rpm.  but as
> the boards pull apart, youll have to take the cosine I beleive of the
> rate or something.
> 
> Chris
> 
>      -----Original Message-----
>      From: astro-photo-bounces@seds.org
>      [mailto:astro-photo-bounces@seds.org]On Behalf Of M/S Heald
>      Sent: Wednesday, March 31, 2004 1:15 AM
>      To: astro-photo@seds.org
>      Subject: [APML] Computerized Barndoor Tracker
> 
>      Hello!  I’d like to get some more information regarding
>      computerized Barndoor Trackers.  As I develop my 4x5 inch
>      camera, it seems that exposures will need to be 10 to 30
>      minutes in duration.  I thought I would try a single arm
>      barndoor tracker instead of piggybacking it to my 8 inch
>      LX200.
> 
> 
> 
>      I saw Tom Kracji’s note from a couple of years ago.  I am
>      not very code or electronics literate, but I can follow
>      explicit directions on making the board and working with the
>      computer code.  Can anyone direct me to info regarding the
>      construction of a daughter board to connect a stepper to an
>      old laptop, and info regarding the code to rive the stepper?
>       Thank you and best regards.
> 
> 
> 
>      Mike Heald
> 
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