3
the Southern Hemisphere, align on the star Sigma Octantis in
the constellation Octans.
setting the Directional switch
Before turning the power switch on, observers in the Northern
Hemisphere should make sure the directional switch is set to
N; Southern Hemisphere observers should set it to S.
Powering up
To begin tracking, slide the power switch to ON. The red LED
power light should illuminate. If it does not, check the connec-
tion between the battery and the terminal connector.
adjusting the tracking speed
The AstroTrack is equipped with adjustable speed control.
Turning the speed control knob clockwise increases the motor
speed, counterclockwise slows it.
Adjustable speed has several benefits. First, it allows you to
achieve a precise sidereal tracking speed for your telescope.
That’s the speed at which most celestial objects appear to
move across the sky. Second, it allows correction for any
deviation from sidereal rate that is inherent in the motor itself.
Third, you can track objects that move at a rate different from
sidereal. The Moon, for instance, moves at a slightly slower
rate, so the motor speed would be reduced.
How do you know when the tracking speed setting is “cor-
rect”? Essentially, when the object in the field of view of the
telescope doesn’t drift. There’s no need to spend a lot of time
precisely canceling the minutest amount of drifting: even with
a small amount of movement, an object will stay in the field of
view for a long period of time.
using the Manual slow-Motion control
Before rotating the R.A. slow-motion cable on the EQ-1
mount, you must first disengage the motor drive. You must do
this whether the power switch is on or off. Disengage the drive
by loosening the coupler’s thumbscrew a few turns. The R.A.
worm gear should then rotate freely when you rotate the slow-
motion control or circular gear (and the coupler should remain
motionless). If you feel it “catch,” loosen the coupler’s thumb-
screw some more until the rotation of the shaft is unhindered.
To re-engage the motor drive, tighten the thumbscrew on the
coupler. Note, however, that to prevent slipping of the cou-
pler on the worm gear shaft, the coupler’s thumbscrew should
lock into the groove on the shaft. You may have to rotate the
R.A. worm gear (using the slow-motion control cable or circu-
lar gear) until the slot lines up with the thumbscrew. Use the
thumbscrew on the R.A. slow-control cable or the mark you
made on the circular gear for reference to line up the groove
and coupler’s thumbscrew. Then tighten the thumbscrew.
Figure 5:
The AstroTrack installed on the EQ-1 mount.
Figure 4:
When the thumbscrews on the R.A. slow-motion
control cable and the drive coupler are rotationally aligned,
the coupler’s thumbscrew should seat into the groove
on the R.A. worm gear shaft.
Thumbscrew
on R.A. slow-
motion control
cable
Thumbscrew
on drive
coupling
Big Dipper
(in Ursa Major)
Little Dipper
(in Ursa Minor)
N.C.P.
Pointer Stars
Polaris
Cassiopeia
Figure 6:
Use the constellation Ursa Major (the Big Dipper) to find Polaris (the North Star). Extend an imaginary line from
two “pointer stars” in the bowl of the Big Dipper, Travel down this line about five times the distance between the two pointer
stars and you will be at Polaris.
