Bushnell 78-9440 manual Selecting an Eyepiece, Viewing Land-Based Objects, Aligning Finderscope

Selecting an Eyepiece:

1.You should always start viewing with the lowest power eyepiece, which in this case is the 12.5mm lens. Note: the base power of each eyepiece is determined by the focal length of the telescope objective lens, which for this model is 700 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 12.5 mm lens, the calculation would look like this: 700 mm ÷ 12.5mm = 56x or 56 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 achieved with the Barlow and Eyepiece configuration alone. The magnification calculation would look like this: 700 mm ÷ 12.5mm = 56 power. 56 power x 2.5=140 power. 56 x 2.5 x 2=280 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. telephone pole or building). Fully extend focusing tube by turning Rack and Pinion

Focusing Mechanism (11).

2.While looking through selected eyepiece (in this case the 12.5 mm), slowly retract focusing tube by turning Rack and Pinion Focusing Mechanism until object comes into focus.

Viewing Land-Based Objects:

1.As described above, the Erecting Lens will correct the normally upside down and reversed image so that you can easily enjoy observing land-based objects through your telescope.

2.Simply insert the Erecting Lens into the focusing tube of the telescope, penta mirror into erecting lens,

then insert an eyepiece into the erecting lens. (See Intended Configuration Diagram).

3.Repeat focusing directions as described above except that you will be looking through the Erecting Lens and eyepiece instead of just the eyepiece.

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 wide field Finderscope (14) 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