Orion PRO 120 EQ Using Your Telescope, Focusing the Telescope, Viewing with Eyeglasses

View through finder scope

View through the SkyView Pro 120 EQ

Figure 5. Images through the finder scope will appear upside- down and backwards (rotated 180°). Images through the SkyView Pro 120 EQ with its diagonal in place will be reversed from left-to right.

en the lock lever on one or both axes and manually point the telescope, it should move without resistance and should not drift from where you point it.

5. Using Your Telescope

Focusing the Telescope

With the 25mm eyepiece inserted in the diagonal, move the telescope so the front (open) end is pointing in the general direction of an object at least 1/4-mile away. Now, with your fingers, slowly rotate one of the focusing knobs 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.

NOTE: The image in the telescope will appear reversed left-to-right. This is normal for astronomical telescopes that utilize a star diagonal. The finder scope view will be rotated 180° (see Figure 5).

If you have trouble focusing, rotate the focusing knob so the drawtube is in as far as it will go. Now look through the eye- piece while slowly rotating the focusing knob in the opposite direction. You should soon see the point at which focus is reached.

The metal thumbscrew on the top of the body of the focuser will lock the focuser drawtube in place once the telescope is properly focused. Before focusing, remember to first loosen this thumbscrew.

Viewing with Eyeglasses

If you wear eyeglasses, you may able to keep them on while you observe, if the eyepiece has enough “eye relief” to allow you to see the whole field of view. You can try this by look- ing 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 they do, you can easily observe with your glasses off by just re-focusing the telescope the needed amount. If you suffer from severe astigmatism, however, you may find images noticeably sharper with your glasses on.

Aligning the Finder Scope

The SkyView Pro 120 EQ comes with a 8x40 achromatic find- er scope (Figure 3a). The number 8 means eight-times magni- fication and the 40 indicates a 40mm diameter front lens. The finder scope makes it easier to locate the subject you want to observe in the telescope, because the finder scope has a much wider field-of-view.

The finder scope uses a spring-loaded bracket that makes alignment of the finderscope very easy. As you turn either of the thumbscrews, the spring in the bracket’s tensioner moves in and out to keep the finder scope secure in the bracket.

The finder scope must be aligned accurately with the tele- scope for proper use. To align it, first aim the main telescope at an object at least a 1/4 mile away—the top of a telephone pole, a chimney, etc. First, loosen the R.A. and Dec. lock levers and move the telescope until it is pointing towards the desired object; sight along the tube to aim the telescope. Turn the focus knob until the object is properly focused. Make sure to position the object in the center of the telescope’s eyepiece by turning the R.A. and Dec. slow-motion control knobs. (The R.A. and Dec. lock levers must be tightened to use the slow- motion control knobs).

Now look in the finder scope. Is the object visible? Ideally it will be somewhere in the field of view. If not, some coarse adjust- ment to the finder scope bracket’s alignment thumbscrews will be needed until the object comes into the finder scope’s field of view.

With the image in the finder scope’s field of view, you now need to fine-adjust the alignment thumbscrews to center the object on the intersection of the crosshairs. Adjust the aim of the finder scope by turning the thumbscrews, one at a time, until the object is centered. Make sure the object is still cen- tered in the telescope’s eyepiece. If it not still centered in the eyepiece you must recenter it and repeat the alignment pro- cess.

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 plan- et, center the object in telescope eyepiece, and then adjust the finder scope bracket’s alignment thumbscrews until the star or planet is centered on the finder’s crosshairs.

Focusing the finder scope

If, when you look through the finder scope, the images appear somewhat out of focus, you will need to refocus the finder scope for your eyes. Loosen the lock ring located behind the objective lens cell on the body of the finder scope (see Figure 3a). Back the lock ring off by a few turns, for now. Refocus the finder scope on a distant object by threading the objective lens cell in or out of the finderscope body. Precise focusing will be

6