Bushnell 78-9540 Manual De Usuario

4.  Insert 

 into focusing tube to begin viewing.

 

1.  You should always start viewing with the lowest power eyepiece, which in this case is the 20 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 540 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

20 mm lens, the calculation would look like this:   540 mm 

÷

 20mm = 27x or 27 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 eyepiece. Using the example above,
your 3x Barlow lens would give you a total power of 81x or 81 power. (27 x 3 = 81x or 81 power)

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 

 

2.  While looking through selected eyepiece (in this case the 20 mm), slowly retract focusing tube by turning

 until object comes into focus.

1.  Look through 

 and establish a well-defined target. (see focusing telescope section)   Tighten

all lock knobs (Declination, Latitude, Right Ascension, and Horizontal Axis)

so that telescope’s aim is not

disturbed.

 

2.  Looking through 

, alternate tightening each

 until crosshairs of

 are precisely centered on the same object already centered in the 

 field of view.

 

3.  Now, objects located first with the 

  will be centered in  the  field  of  view  of  the  main

telescope

.