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Re: ATM project idea
> I played with an LX200 at RTMC and was VERY impressed with the goto
> capabilities - althjough less so with the optics. How hard would it be to
> get that same functionality with a computer driving standard
> autoguider-enable mounts? Could an interface of some sort be done which
> would allow an autoguider enabled mount to be controlled as if it was an
> LX200 since so many software programs seem to support LX200 control codes?
What follows it's a bit long.......
I'm very interested in this subject too for the same reason (supporting
software) and for other reasons as well.
As I see there exist two problems:
1.- To know the LX200 interface, both physical and logical:
a. What type of interface? (I suppose RS-232).
b. Which protocol? (I remember some I've read about it and it's as
simple as an "ASCII" protocol, the controller issue orders to the
telescope and the telescope answers with its status and position,
both with ASCII chains of characters).
2.- What is the "autoguider-enable mount" named above. I suppose it has drives
and some way of controlling them. Again we run into what type of physical
interface it has and the protocol it uses.
and a fact:
the telescope to be controlled must have a good mount and driving in order
to mimmic the precission I suppose you have seen in the LX200.
In the following paragraphs I'll supose you want to control your telescope
(not an LX200) with a PC and your favorite planetarium-like program running on
it.
1.---------------------
In the case of both the "autoguider-enable mount" and the LX200 use RS-232 and
both protocols are known what you need is a "protocol switch" to translate
from LX200 protocol to the protocol used by your telescope. I think in this
case the best approach is to have three RS-232 ports in your PC, four if you
use the mouse on one of then (usually a
PC has two serial ports, and the cards to add another two are not expensive).
Then, all you need
is the software to switch between both (your telescope & LX200) protocols,
plug your telescope to serial port 0, and chain the serial ports 1 and 2; after
that you run your "software protocol-switch" on ports 0 and 1, and tell your
planetarium to use serial port 2 to control the telescope. It's necessary for
this to run to use an operating system as Windows 95-NT-3.11, Lynux in order
to allow running several processes on the PC simultaneously (probably it may
be done in MS-DOS alone with device drivers too).
That is, all you need is to know the protocols, buy the serial port expansion,
and build the program to switch from one telescope's protocol to the other.
A more elegant version of this is to have an external box to do the switch and
plug it between your PC and your telescope; this must not be complicated if
you use one of these little controllers like the 8051 or others and (this is
the problem) the skills to do and program the box. In this case the box may be
intelligent enough to control the telescope without the PC (that is, this
configuration may be used with the PC, or portable without the PC).
2.--------------------------------------------------
The approach above may be applicable to Mel Bartels (what do you think Mel ?)
design but using two serial ports and the paralell port (sofware approach) or
using the box with a serial port and a paralell port (hardware approach), but in
this case the box may be a bit complicated to program, because you have the
problem of porting Mel's control program to the processor on the box (again I
consider this more elegant, in fact you build a "Meade Telescope" with Mel's
design inside).
This aproach is also useful if the telescope to control has a parallel
interface too.
3.---------------------------------------------------
Other type of interfaces: this has to be defined to reach the optimum
(and effortless) approach.
Any comments wellcome, clear skies .........
Jose M. Chercoles (jmch@cosmos.tid.es)