Bushnell 78-9470 manual Selecting an Eyepiece, Aligning Finderscope

1.Basic Description: In addition to our revolutionary Penta Mirror Technology, Bushnell is proud to present yet another pioneering feature with this telescope--Bushnell’s ZOOM Eyepiece Assembly. This assembly will provide the benefit of instantaneously zooming from 50 power to 150 power with a twist of the power change ring. Little if any refocusing will be required. This feature gives your telescope an infinite number of magnification levels from 50x to 150x. Not only is this a convenient new feature to the astronomical community but it also provides an erect (or “right-side-up”) image. As a result, astronomers, birdwatchers, nature enthusiasts and many others can enjoy the convenient and intuitive images seen through this telescope.

2.How-To-Use:Place the ZOOM Eyepiece Assembly directly into the rear of the Penta Mirror Assembly with grooved insert, then place the Penta Mirror directly into the back of the telescope focusing tube. (See Intended Configuration Diagram). CAUTION: DO NOT USE THE ZOOM

EYEPIECE WITH THE ERECTING LENS OR BARLOW IN ANY POSSIBLE CONFIGURATION

Selecting an Eyepiece:

1.You should always start viewing with the lowest power eyepiece, which in this case is the 15 mm lens. Note: the base power of each eyepiece is determined by the focal length of the telescope objective lens, which for this model is 750 mm. A formula can be used to determine the power of

each eyepiece: telescope OBJECTIVE lens focal length EYEPIECE focal length =

MAGNIFICATION (e.g. Using the 15 mm lens, the calculation would look like this: 750 mm ÷ 15mm = 50x or 50 power.)

2.Included with this telescope is a Barlow lens. Barlow lenses are used to double or triple the power of your telescope. Place your Barlow between the focusing tube and the penta mirror. Note: The

Penta Mirror Assembly when used in conjunction with the Barlow Lens and Eyepiece as shown in the Intended Configuration Diagram will yield an effective doubling power of the

magnification already acheived with the Barlow and Eyepiece configuration alone. The magnification calculation would look like this: 750 mm ÷ 20mm = 38 power. 38 power x 3=114 power. 38 x 3 x 2=228 power. (See Intended Configuration Diagram).

Focusing Telescope:

1.After selecting the desired eyepiece, aim main telescope tube at a land-based target at least 200 yards away (e.g. A telephone pole or building). Fully extend focusing tube by turning Rack and

Pinion Focusing Mechanism (13).

2.While looking through selected eyepiece (in this case the 20 mm), slowly retract focusing tube by turning Rack and Pinion Focusing Mechanism until object comes into focus.

Aligning Finderscope:

Look through main telescope tube at low power and establish a well-defined stationary target. Looking through red dot finderscope, alternate tightening each adjustment wheel (at rear and left side of finderscope) until the red dot of finderscope is precisely aligned and centered on the same object being viewed in main telescope tube. See finderscope page.

Now, objects located first with the Finderscope (16) will be centered in the field of view of the main telescope.

Never Look Directly At The Sun With Your Telescope

Permanent Damage To Your Eyes May Occur