From: martin.cibulski{at}t-online.de (Martin Cibulski)
To: 
Reply-To: martin.cibulski{at}t-online.de (Martin Cibulski)


Greg,

I built a microcontroller based telescope driver. I use an Atmel megaAVR
161 microcontroller and Allegro 3973 stepper drivers (with microstepping).

Have a look at:
http://martin.cibulski.bei.t-online.de/

The current operational release can be used manually with a simple handbox.
Additionally the microcontroller communicates with a PC which does the
coordinate transformation from steps to rightascension and declination
(still under development).

A next development step could be an intelligent handbox with a more
powerful AVR controller and a small display. Then the PC is obsolete and
will only be used for more complicated calculations like finding mount
errors from a 'multi star alignment'.

If you have comments on my website I would like to read them.

Best Regards,
Martin Cibulski

>>
From: Emery Greg 
Subject: ATM: Field Rotation and GoTo Scopes

Hello All:

The recent threads on Alt-Az, Alt-Alt scopes and field rotation and on goto
scopes encouraged me to write/share something.

About 3 months ago I was toying with the idea of building my own goto
system to go with the 200 mm f/5 bino's I am just starting to build.  I
will describe what I was considering.  I postponed the project due to lack
of funds and time, I believe it is conceptually sound.

In place of a laptop computer use a micro-controller board or a single
board computer.  A separate stepper motor will drive each axis ( as well as
the field de-rotator if desired).  Fine tuning movement, database object
selection for goto, slew rate can all be controlled from a keypad.  System
alignment can be done from a three or four star calibration routine.

This is all pretty standard, the neat thing however is, a substitution can
be made for standard EEPROM on the controller boards, upgrading to 64 KB,
1MB or whatever of EEPROM.  The boards I was looking at, had EEPROM writing
in-circuit.  ( Some models had the EEPROM option replacable by Megabyte
level NVRAM).  A database of objects can be downloaded at the time of
downloading the control program, and it will stay resident.  Additional
inputs and outputs could be used for a joystick and LCDs for  RA and Dec.

The math and programming is not difficult, compacting the database to
optimize for time and size could be harder, but the programming can be done
in Basic, C, Hex, Assembler depending on your likes and the hardware you
choose.

In terms of hardware I was looking at Motorola 68HC11's and Zilog Z80 based
boards.  For Intel chips I was considering a 80386 family SBC.

Has anyone done something similar, or planned on doing it?

ttfn
Greg
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