telescope to move.  Momentarily pushing down the opposite button while the telescope is 

moving causes it to accelerate to the next higher movement speed.  

The Hand Controller works in one of three modes: the Visual Mode, the Photo Mode and 

the All Speeds Mode. You can move both axes simultaneously in all 3 modes. You select 

the mode by means of the Setup

Hand Controller menu item. Like some other settings, 

it is remembered permanently and will be in effect even after powering off and on again.  

The Visual Mode

In visual mode, the Guiding Speed is not available. When you press a button, the 

telescope moves with Centering Speed.  Momentarily pushing the opposite button lets the 

system accelerate to the manual slewing speed.  If you are moving both axes, both will 

speed up.  Ramping up and down in speed occurs independently for both axes.  

This mode is intended for visual observing and for looking up objects. The autoguider 

port is not active in this mode.  

The Photo Mode

In Photo Mode, Guiding Speed is the principal speed, so pressing a Hand Controller 

directional button moves the telescope at the selected Guiding Speed; Slewing Speed is 

not available.  Acceleration to Centering Speed is available in four stages (to allow easy 

centering of an object in the field of view or on a CCD chip) by pressing the opposite 

button while Gemini is guiding:  

 Pressing the opposite button once changes to 1/8 of Centering Speed to allow fine 

centering of the target.  Then, after about 2 seconds, the speed will increase to   

Centering Speed, after another 2 seconds to   Centering Speed, and finally to full 

Centering Speed. 

Pressing the opposite button twice changes to full Centering Speed immediately.  

If you want to guide a photograph manually, you may plug a Standard (not Deluxe) Hand 

Controller into Gemini's autoguider port. This way you are sure that you cannot 

accidentally move the scope at centering speed while guiding.  The LED on the standard 

Hand Controller will not be illuminated when plugged into the autoguider port.  

The All Speeds Mode

In this mode, all speeds are available, from Guiding Speed to Slewing Speed, by using 

the opposite button trick. You can use this mode, for example, while drift aligning, when 

you need very fine centering of a star at the crosshairs and a fast move from the meridian 

to the eastern or western horizon. However, for normal observing, you 

ll probably select 

either the Visual or Photo Mode.  

Gemini Users Manual 

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