Re: [guide-user] Scope Control

Bill J Gray Sep 30, 2004

Hi Al,

Hmmm... this one will be a bit tricky, I'm afraid. You're
basically looking to "mix-and-match" the JMI/MG-III encoder
system (which doesn't involve motors) with the AltAz one
(which does).

As you recalled, there's a way to get Guide to read
"encoder" data from a file, rather than from a serial port.
The first step would be to put Guide into JMI/MG-III mode. You
_could_ do that by editing 'startup.mar' and setting 'enc syst 4',
but it would be simpler to fire up Guide and click on Settings...
JMI/MG-III.

Next step, to tell Guide to read encoder locations from a
file rather than a serial port: hit Alt-J and enter

SCOPE_DATA_FILE=slew_out.dat

or whatever file name you want to use. The encoder positions
must be stored in this file as integer values, 7 bytes apiece
(for example, " 31415 26535".) Anything after the 14th byte
in the file is simply ignored.

However, if you're in JMI/MG-III mode, there's no way to
get those motors moving; Guide will assume that the scope just
has encoders, without motors. To duck around this, you'll
want to go to the Scope Control dialog and switch to AltAz.

When you do this, clicking on "Slew Scope" will produce the
'slew.dat' file loaded with RA/dec and alt/az and field rotation
data, with which you're probably familiar. Clicking on "Slew
Guide" will cause Guide to read the telescope position from the
file 'slew_out.dat'. Guide will assume that this file contains
the RA/dec, in decimal degrees. Clicking on the relatively new
"Toggle Scope Location Indicator" toolbar button will toggle the
little symbol indicating where the scope is pointed; Guide will
re-check the 'slew_out.dat' file every second or so to see if the
scope has moved.

-- Bill