accomplishes this by comparing the apparent modeled coordinates of the object being 

tracked with the actual coordinates of the telescope, and makes slow RA and Dec. 

corrections.  Although an object can usually be kept centered using this technique, field 

rotation occurs if there is polar misalignment.  See Chapter 3, section 3.3.1.4 of this 

manual for further details. 

"Comet/User Def." tracking is a tool that allows you to set independent RA and Dec. 

tracking rates to track comets and other solar system objects that follow unique 

trajectories.  This menu item contains a submenu of three additional items which are 

"Train Tracking," "Calculate Rates" and "Activate" (reselecting a previously trained, 

calculated, or PC downloaded rate). See Chapter 3, section 3.3.1.5 of this manual for 

details on how to use this feature. 

5.3.10.2.2  Moving Speeds 

Guiding

Centering

Slewing

GoTo

The "Moving Speeds" entered through this menu are accessed when the telescope is 

moved by means of the Hand Controller or a during a GoTo operation. 

"Guiding" is the slowest of the "Moving Speeds"; it can be set within a range of 0.2 to 0.8 

of the tracking speed.  While guiding occurs at constant speed in Dec., it adds to or 

subtracts from, the tracking speed in RA.  For example, a "Guiding" speed of 0.5 

increases RA tracking to 1.5 when guiding with the RA+ button of the Hand Controller, 

and reduces it to 0.5 when guiding with the RA  button. 

"Centering" speed is intended to be faster than "Guiding," but slower than "Slewing."  It 

can be set as high as 255 times "Sidereal" speed, and should be set to the comfort of the 

observer for centering objects in the telescope's field of view. 

"Slewing" speed is for moving the telescope over long distances using either the Hand 

Controller or PC slewing control.  It is set by default to 800 times "Sidereal" speed, and it 

ramps down in speed when you release the Hand Controller button.  If your mount is 

slewing reliably without straining or stalling at the default speed, you may be able to 

increase the speed to as much as 1200 times sidereal rate. 

"GoTo" speed is for moving the telescope over relatively long distances during a GoTo 

operation initiated from either the hand controller or PC software.  As with "Slewing,   

the "GoTo" speed can be set as high as 1200, but the telescope mount often operates 

more effectively if it is left at the default value of 800.  In order not to overshoot its 

target, GoTo slews ramp down to "Centering" speed as the telescope approaches its 

destination object. 

Gemini Users Manual 

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