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the telescope where it is. You can also do this by hitting F12 or Ctrl-F2 at any point in Guide. Also, if you have toggled to the Sky Commander and have selected its port, you can copy a list of positions from Guide to the Sky Commander. You can then take the Sky Commander into the field and observe those objects. This is further described in the section on the User Object menu, on page 38. One note about the "Alt/Az" system. This button corresponds to a stepper-motor system designed by Mel Bartels and used by several Dobsonian owners. The advantages of the Alt/Az system are simplicity, good precision, and very low cost. The system consists of stepper motors added to the altitude and azimuth axes, and driven by the PC. All of the "intelligence" for alignment, etc. is in the Alt/Az software, making for very minimal hardware requirements. If you have an interest in connecting your own, customized computer-controlled telescope to Guide, you may wish to check the file \COMPRESS\XTROL.DOC on the DVD-ROM. It contains some data on how communication with LX-200 and ALTAZ systems is done by Guide. 11a: Encoder-based systems As was mentioned above, handling alignment of JMI/MG-III type systems ("Tangent Instrument boxes") is a somewhat different process from that required for other systems. The other systems have built-in hardware to handle alignment. Tangent Instrument boxes require Guide to handle that task. To use your JMI/MG-III compatible encoders, hook up the interface to the computer, start Guide, and click on "Settings... Telescope Control". Select the serial port used for the encoders; this is usually COM2, but it may be COM1 on some laptops. And in some odd cases, it may be COM3 or COM4. Also, select the "JMI/MG III" radio button, and enter the scope resolution in the boxes at the bottom of the dialog. Click OK. After a short pause, Guide will provide a "Scope resolution successfully set" message, and will add the "Scope Pad" option to the menu bar. (If it shows any other message, then Guide has been unable to set the encoder resolution correctly. Check the encoder connections and make sure the COM port has been set up correctly.) If Guide succeeds in communicating with the scope, it will move to the next step. You'll see a small dialog box, asking if you have an "equatorial reading hour angle", an alt/az, an alt/az scope on an equatorial platform, or an equatorial reading RA. The alt/az options are straightforward enough, but the equatorial options require some explanation. It seems that encoders on equatorial scopes are about evenly divided between two mounting methods. Some
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