Setting Up and Using the Equatorial Mount

2.Now loosen the counterweight lock knob and slide the weight along the shaft until it exactly counterbalances the tele‑ scope (Figure 3a). That’s the point at which the shaft remains horizontal even when you let go of the telescope with both hands (Figure 3b).

3.Retighten the counterweight lock knob.

The telescope is now balanced on the R.A. axis. It is not nec‑ essary to balance the telescope on the Dec. axis, since the optical tube’s mounting block is positioned so that the tele‑ scope will automatically be balanced on that axis. Now when you loosen the lock knob on one or both axes of motion and manually point the telescope, it should move without resis‑ tance and should not drift from where you point it.

Focusing the Telescope

Point the telescope so the front end is aimed in the general direction of an object at least 1/4-mile away. Now, with your fingers, slowly rotate the focusing knob until the object comes into sharp focus. Go a little bit beyond sharp focus until the image just starts to blur again, then reverse the rotation of the knob, just to make sure you’ve hit the exact focus point.

If you have trouble focusing, rotate the focus knob counter- clockwise as far as it will go. Now look through the eyepiece while slowly rotating the focus knob clockwise. You should soon see the point at which focus is reached.

Do You Wear Eyeglasses?

If you wear eyeglasses, you may be able to keep them on while you observe. In order to do this, your eyepiece must have enough “eye relief" to allow you to see the entire field of view with glasses on. You can try this by looking through the eyepiece first with your glasses on and then with them off, and see if the glasses restrict the view to only a portion of the full field. If the glasses do restrict the field of view, you may be able to observe with your glasses off by just refocusing the telescope the needed amount.

If your eyes are astigmatic, images will probably appear the best with glasses on. This is because a telescope’s focuser can accommodate for nearsightedness or farsightedness, but not astigmatism. If you have to wear your glasses while observing and cannot see the entire field of view, you may want to purchase additional eyepieces that have longer eye relief.

Aligning the Finder Scope

The finder scope (Figure 4) must be aligned accurately with the telescope for proper use. To align it, aim the main tele‑ scope in the general direction of an object at least 1/4-mile away, such as the top of a telephone pole, a chimney, etc. Do this by first loosening the R.A. and Dec. lock knobs. Position the telescope so the object appears in the eyepiece’s field of view and then retighten the R.A. and Dec. lock knobs. Use the slow-motion control cables to center the object in the eye‑ piece.

Now, look in the finder scope. Is the object visible? Ideally, it will be somewhere in the finder’s field of view. If it is not, some coarse adjustments of the three black nylon finder scope

Nylon thumbscrew
O-Ring
(not shown)
		Rubber
		eyeguard
Objective		Nylon
lens		thumbscrew
Finder scope		Finder scope
		bracket

Figure 4: The 6x20 Correct-Image finder scope and bracket

alignment thumbscrews will be needed to get the finder scope roughly parallel to the main tube.

Note: The image in the telescope’s eyepiece will appear inverted from left-to-right (mirror reversed), which is normal for telescopes that utilize a star diagonal. The image in the finder scope is oriented the same as the naked eye.

Use the three nylon thumbscrews to center the object on the crosshairs of the finder scope. Then look again into the tele‑ scope’s eyepiece and see if the object is still centered there as well. If it isn’t, repeat the entire process, making sure not to move the main telescope while adjusting the alignment of the finderscope.

The finder scope alignment needs to be checked before every observing session. This can easily be done at night, before viewing through the telescope. Choose any bright star or planet, center the object in the telescope eyepiece, and then adjust the finder scope’s alignment screws until the star or planet is also centered on the finder’s crosshairs. The finder scope is an invaluable tool for locating objects in the night sky; its usage for this purpose will be discussed later, in detail.

Focusing the Finder Scope

If, when looking through the finder scope, the images appear somewhat out of focus, you will need to refocus the finder scope for your eyes. Turn the end of the finder scope with the rubber eyeguard clockwise or counter-clockwise as needed to focus the finder scope on a distant object (1/4 mile away or more). Precise focusing will be achieved by focusing the finder scope on a bright star.

5.Setting Up and Using the Equatorial Mount

When you look at the night sky, you no doubt have noticed that the stars appear to move slowly from east to west over time. That apparent motion is caused by the Earth’s rotation (from west to east). An equatorial mount (Figure 2) is designed