Orion 9964 Using your telescope, Aligning the EZ Finder, Replacing the EZ Finder II Battery

skies and a bright setting is used under light-polluted skies or in daylight.

Azimuth adjustment knob

Power knob

	Battery
	casing
Altitude	Mounting bracket
adjustment
knob

Figure 6. The EZ Finder II reflex sight.

At the end of your observing session, be sure to turn the power knob counterclockwise until it clicks off. When the two white dots on the EZ Finder II’s rail and power knob are lined up, the EZ Finder II is turned off.

Aligning the EZ Finder II

When the EZ Finder II is properly aligned with the tele- scope, an object that is centered on the EZ Finder II’s red dot should also appear in the center of the field of view of the telescope’s eyepiece. Alignment of the EZ Finder II is easiest during daylight, before observing at night. Aim the telescope at a distant object at least 1/4 mile away, such as a telephone pole or chimney and center it in the telescope’s eyepiece. Now, turn the EZ Finder II on and look through it. The object will appear in the field of view near the red dot.

Note: The image in the eyepiece of the StarBlast 6 will be upside-down (rotated 180°). This is normal for Newtonian reflector telescopes.

Without moving the telescope, use the EZ Finder II’s azi- muth (left/right) and altitude (up/down) adjustment knobs (Figure 6) to position the red dot on the object in the eye- piece.

When the red dot is centered on the distant object, check to make sure the object is still centered in the telescope’s field of view. If not, recenter it and adjust the EZ Finder II’s align- ment again. When the object is centered in the eyepiece and on the red dot, the EZ Finder II is properly aligned with the telescope. Figure 7 shows how the view through the EZ Finder may look while you are aligning it.

Once aligned, EZ Finder II will usually hold its alignment even after being removed and remounted. Otherwise, only minimal realignment will be needed.

Replacing the EZ Finder II Battery

Replacement 3-volt lithium batteries for the EZ Finder II are available from many retail outlets. Remove the old battery by inserting a small flat-head screwdriver into the slot on the battery casing (Figure 6) and gently prying open the case. Then carefully pull back on the retaining clip and remove the old battery. Do not overbend the retaining clip. Slide the

new battery under the battery lead with the positive (+) side facing down and replace the battery casing.

Figure 7.

The EZ Finder II superimposes a tiny red dot on the sky, showing right where the

telescope is pointed.

Using your telescope

Choosing an Observing Site

When selecting a location for observing, get as far away as possible from direct artificial light such as street lights, porch lights, and automobile headlights. The glare from these lights will greatly impair your dark-adapted night vision. Avoid viewing over rooftops and chimneys, as they often have warm air currents rising from them. Similarly, avoid observing from indoors through an open (or closed) window, because the temperature difference between the indoor and outdoor air will cause image blurring and distortion.

If at all possible, escape the light-polluted city sky and head for darker country skies. You’ll be amazed at how many more stars and deep-sky objects are visible in a dark sky!

“Seeing” and Transparency

Atmospheric conditions vary significantly from night to night. “Seeing” refers to the steadiness of the Earth’s atmosphere at a given time. In conditions of poor seeing, atmospheric turbulence causes objects viewed through the telescope to “boil”. If, when you look up at the sky with your naked eyes, the stars are twinkling noticeably, the seeing is bad and you will be limited to viewing with low powers. This is because bad seeing affects images at high powers more severely. Planetary observing may also be poor.

In conditions of good seeing, star twinkling is minimal and images appear steady in the eyepiece. Seeing is best over- head, worst at the horizon. Also, seeing generally gets bet- ter after midnight, when much of the heat absorbed by the Earth during the day has radiated off into space.

Especially important for observing faint objects is good “transparency” - air free of moisture, smoke, and dust. All tend to scatter light, which reduces an object’s brightness. Transparency is judged by the magnitude of the faintest stars you can see with the unaided eye (6th magnitude or fainter is desirable).

If you cannot see stars of magnitude 3.5 or dimmer then conditions are poor. Magnitude is a measure of how bright

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