Scope control comments
This page will eventually supersede the original comments on hooking up customized telescope systems to Guide.
Hooking up non-motorized scopes to Guide
Most people with encoders on their scopes run them through an interface of the JMI/MG-III compatible type. (This includes the Lumicon, Orion Sky Wizard, Celestron Advanced Astro-Master, Ouranos, and various others made by Tangent Instruments.) About 90% of interfaces are in this category. They all have different built-in databases, but from the viewpoint of a PC, they're identical. You can hook up Guide to such a system quite easily, by selecting the 'JMI/MG-III compatible' radio button in Settings... Scope Control, choosing the COM port, and setting the encoder resolution.
Most of the remaining commercially-available encoder interfaces are provided by Sky Commander. Some have been resold through Losmandy. These are similarly easy to use in Guide, by selecting the 'Sky Commander' radio button instead.
People who build their own encoder-based systems usually have to figure out something different. Guide 7 includes a feature that makes hooking up such custom encoder systems somewhat easier than it once was.
How it works: The method requires that you write your own driver program that through some method or another can read your telescope encoders. From the viewpoint of Guide, the innards of how those encoders work and how your software works are irrelevant. Your driver program should, about once a second, write the encoder positions to a text file. Guide will, once a second, read that file.
From Guide's point of view, the system works 'just like' a JMI/MG-III compatible device. The only difference, as far as Guide is concerned, is that it no longer gets the encoder position from a serial cable. It gets it from your driver program instead, via the text file.
What your driver must do: The encoder position should be written to the text file as two integer values. The first integer value should consume 7 bytes, and give the encoder position on the RA axis (for an equatorial scope) or the azimuth axis (for an alt/az scope). The second integer values should also consume 7 bytes, and gives the encoder position on the remaining axis.
Theoretically speaking, your driver routine should re-write that file once a second with an updated position. Practically speaking, if you don't update it frequently, Guide just won't update the scope position on-screen as frequently.
What you have to do in Guide: Before you even start Guide, you have to add the following line to GUIDE.DAT:
SCOPE_DATA_FILE=(filename)
where (filename) is the name of the 14-byte data file your scope driver routine is producing. As you might expect, this just tells Guide to look for encoder data in that file, rather than from the serial port. Also, of course, make sure your scope driver program is running!
Once that's done, the remainder of the work in Guide is almost exactly as you would do for a "normal" JMI/MG-III compatible system, and the text in the manual may be helpful. You have to go into Settings... Scope Control, select the 'JMI/MG-III' radio button, set the resolution on each axis, and select a COM port (it doesn't matter which one, in this case).
Click 'OK' to exit the scope control dialog, and you'll be asked which type of scope you have, and then the Scope Pad dialog will appear. You can select alignment stars and, in general, act just as if you had a JMI/MG-III style interface.