Orion 130ST EQ instruction manual Getting Started, Balancing the Telescope

Alignment thumbscrews

Focus lock ring

Tensioner Objective

lense

Finder Scope Bracket

Figure 3a. The 6x30	Figure 3b. Inserting the
finder‑scope.	finder scope into the finder scope
	bracket

your fingers (Figure 3b). Push the finder scope through the bracket until the O-ring seats just inside the front opening of the bracket’s cylinder. Now, release the ten- sioner and tighten the two black nylon screws a couple of turns each to secure the finder scope in place.

13.Insert the base of the finder scope bracket into the dove- tail slot near the focuser. Lock the bracket into position by tightening the knurled thumb screw on the dovetail slot.

14.Remove the cap from the focuser and insert the chrome barrel of one of the eyepieces into the drawtube. Secure the eyepiece with the thumb screws on the drawtube. Remember to always loosen the thumb screws before rotating or removing the eyepiece.

The telescope system is now fully assembled. Keep the dust cap over the front end of the telescope when it is not in use.

4. Getting Started

Balancing the Telescope

To insure smooth movement of the telescope on both axes of the equatorial mount, it is imperative that the optical tube be properly balanced. We will first balance the telescope with respect to the R.A. axis, then the Dec. axis.

1.Keeping one hand on the telescope optical tube, loosen the R.A. lock knob. Make sure the Dec. lock knob is locked, for now. The telescope should now be able to rotate freely about the R.A. axis. Rotate it until the coun- terweight shaft is parallel to the ground (i.e., horizontal).

2.Now loosen the counterweight lock knob and slide the weight along the shaft until it exactly counterbalances the telescope (Figure 4a). That’s the point at which the shaft remains horizontal even when you let go of the telescope with both hands (Figure 4b).

3.Retighten the counterweight lock knob. The telescope is now balanced on the R.A. axis.

4.To balance the telescope on the Dec. axis, first tighten the R.A. lock knob, with the counterweight shaft still in the

a.

b.

c.

d.

Figure 4. Proper operation of the equatorial mount requires that the telescope tube be balanced on both the R.A. and Dec. axes. (a) With the R.A. lock knob released, slide the counterweight along the counterweight shaft until it just counterbalances the tube. (b) When you let go with both hands, the tube should not drift up or down. (c) With the Dec. lock knob released, loosen the tube ring lock clamps a few turns and slide the telescope forward or back in the tube rings. (d) When the tube is balanced about the Dec. axis, it will not move when you let go.

5