Equinox Systems GEMINI Instrukcja Użytkownika Pobierz pdf (Strona 35)

Gemini Users Manual 30

Training Comet Tracking

When you select “Setup→Mount Parameter→Tracking Speed→Comet Tracking→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

timer’s range, an RA timer value of 65535 (the maximum value) will be displayed and

used instead.

Coordinate Controlled Tracking

Calculating the tracking rate using coordinates is useful if you want to track an object for

which you have an ephemeris. Knowing 2 different positions of the object at different

times, Gemini can calculate the speed required to track the object. You can use the

“Setup→Mount Parameter→Tracking Speed→Comet Tracking→Calculate Rates” menu

item to enter coordinates from an ephemeris for the object you want to observe. Gemini

asks for three pieces of data: two sets of object coordinates, and the amount of elapsed

time (in hours) between them. The coordinate difference is used to calculate the

necessary tracking rates in both RA and Dec. Since only the difference is used, the

coordinates need not reflect the exact location of the object at the current time. If the RA

value is outside the possible range, the input will be rejected.

If the coordinates change very slowly, you can multiply all values (RA, Dec. differences

and the time interval) by a constant to input them with increased accuracy.

Timer Values

Comet Tracking allows you to manually enter rates for both RA and Dec. In both cases,

these are divisor values that are used to divide the timer frequency to calculate the rate at

which the motors are driven.

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Equinox Systems GEMINI Instrukcja Użytkownika Strona 35