Training

   Train the tracking by centering on the initial and the end position of an 

object over an interval of time 

Coordinate Controlled

   Enter the RA/DEC positions at the start and at the end 

of an interval of time 

PC Controlled

   Calculate the necessary tracking rates at a PC and download 

them to the Gemini. 

For each of these methods, a new tracking value for Gemini' s internal timer that controls 

the tracking speed will be calculated and loaded.  The available timer range limits the 

lowest possible speed.  Faster tracking (moving towards smaller RA values) does not 

have this limitation. 

Since declination usually changes very slowly, Gemini does not use an internal timer for 

Dec.  Instead, Gemini calculates (or is told by a computer) the number of RA steps to be 

done for each Dec. step.  Positive DEC rates mean that the Dec. values are getting higher 

with time.  Upon reaching the pole, the direction will not be changed.  After crossing the 

pole, Dec. will decrease.  

The Comet/User Defined tracking values are preserved as long as the Gemini is not 

powered down.  The programmed rate can be activated again (after another tracking rate 

was used) with the   Setup

Mount Parameter

Tracking Speed

Comet/User 

Def

Activate   menu item.  If the Gemini was powered down while in Comet/User 

Defined tracking mode, it will start up in Sidereal mode. 

Training Comet Tracking 

When you select   Setup

Mount Parameter

Tracking Speed

Comet/User Def

Train 

Tracking,   a training phase is started.  Unlike training PEC, you don 

t have to follow the 

motions exactly. Just keep the object in the eyepiece for a sufficient amount of time.  

Finally, center it and press the MENU button to end the training phase.  Gemini 

calculates the necessary tracking rates in RA as well as in DEC and the mount will follow 

the object in both axes. 

The amount of time needed for training will vary with the object and the type of 

observation.  For an object with a relatively slow and constant motion, a few minutes of 

training should be sufficient for visual observing.  For photography, you may want to 

consider training for up to half of the intended exposure time.  For an object that changes 

speed fairly quickly (such as a Near Earth Asteroid), shorter training sessions just before 

the observation will work best.  In general however, for an object with relatively constant 

speed, the longer the training (up to 45 minutes) and the more exactly the object is 

centered at the beginning and end of training, the better the tracking will be. 

After the training,   Show Information   displays the number of steps done and timer 

values calculated.  If the training reveals an RA motion too slow to follow within the RA 

Gemini Users Manual 

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