background image

TELESCOPE USE

SELECTING AN EYEPIECE:

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 element, which for this model is 900 mm.  A formula can be used to
determine the power of each eyepiece: 

telescope OBJECTIVE mirror focal length 

EYEPIECE focal length = MAGNIFICATION

 (e.g. Using the 20 mm lens, the calculation

would look like this:   900 mm 

÷

 20mm = 45x or 45 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)

3.

 

Other accessories available include a 9mm eyepiece (model #78-0101) and a standard camera
adapter (model #78-0104) for photographing the night sky.

FOCUSING TELESCOPE:

1.

 

After inserting the eyepiece, aim the 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 &
Pinion Focusing Mechanism

 

(1)

 

2.

 

While looking through selected eyepiece (in this case the 20 mm), slowly retract focusing
tube by turning Rack & Pinion Focusing Mechanism

 

(1) until object comes into focus.

ALIGNING FINDERSCOPE:

1.

 

Look through low-power 1.25" format eyepiece (8) and establish a well-defined target (see
focusing telescope section).

2.

 

Looking through Finderscope (7), alternate tightening each

 

Finderscope Adjustment Screw

surrounding the Finderscope (7) in the Finderscope Mount until crosshairs of Finderscope (7)
are precisely centered on the same object already centered in Main Telescope Tube's field of
view as seen through the 1.25" Format Eyepiece (8).

 

3.

 

Now, objects located first with the Finderscope (7) will be centered in the field of view of the
main telescope as seen through the 1.25" Format Eyepiece (8).

Enjoying Your New Telescope

1.  First determine your targeted object.  Any bright object in the night sky is a good starting

point.  One of the favorite starting points in astronomy is the moon.  This is an object sure to
please any budding astronomer or experienced veteran.  When you have developed
proficiency at this level, other objects become good targets.  Saturn, Mars, Jupiter, and Venus
are good second steps to take.

2.  The first thing you need to do after assembling the telescope as planned is center the desired

object in the finderscope's cross hairs.  Provided you did a reasonable job aligning the
finderscope, a quick look through the main telescope tube at low power should reveal the
same image.  With the lowest power eyepiece (the one with the largest number printed on it)
you should be able to focus the same image that you saw through the finderscope.  Avoid the
temptation to move directly to the highest power.  The low power eyepiece will give you a
wider field of view, and brighter image--thus making it very easy to find your target object.

Summary of Contents for VOYAGER 78-4500

Page 1: ...ctly At The Sun With Your Telescope Permanent Damage To Your Eyes May Occur 1 Rack Pinion Focusing System 5 Dobsonian Base Azimuth Bearing 2 Reflector Body 6 Primary Mirror 3 Altitude Bearing 7 Finderscope 4 Dobsonian Side Panel 8 1 25 Format Eyepiece 1 2 3 4 5 6 7 8 ...

Page 2: ...you travel on your journey through the universe READ THROUGH ASSEMBLY INSTRUCTION BEFORE YOU ASSEMBLE YOUR TELESCOPE TELESCOPE ASSEMBLY INSTRUCTIONS Your Bushnell Voyager Dobsonian Telescope comes preassembled from the factory By simply attaching the accessory finderscope and eyepiece you will be ready to explore ATTACH FINDERSCOPE 1 Remove Reflector Telescope Assembly 2 and Finderscope 7 from car...

Page 3: ...rmat eyepiece 8 and establish a well defined target see focusing telescope section 2 Looking through Finderscope 7 alternate tightening each Finderscope Adjustment Screw surrounding the Finderscope 7 in the Finderscope Mount until crosshairs of Finderscope 7 are precisely centered on the same object already centered in Main Telescope Tube s field of view as seen through the 1 25 Format Eyepiece 8 ...

Page 4: ... that the earth is rotating about its axis As a result you may notice that after a few minutes or a few seconds depending on what power you are viewing at the objects in your telescope will move At higher magnifications especially you will notice that the moon or Jupiter will race right out of the field of view To compensate just move the fine adjustment controls on your telescope to track it in t...

Page 5: ...rk stripes or bands both above and below its equator These are the north and south equatorial belts Also interesting are Jupiter s four major moons Pay close attention to their positions from night to night They appear to be lined up on either side of Jupiter Mars The Great Red Planet appears as a reddish orange disk Look at different times of the year and try to catch a glimpse of the white polar...

Page 6: ... What do the numbers on the eyepiece mean The numbers on the eyepiece represents the focal Length of the eyepiece TROUBLESHOOTING GUIDE If after you have set up your new telescope you are unable to see any objects use this Quick Reference guide to help you to understand the cause of the problem and quickly determine a remedy 1 I ve completed the set up yet I cannot see anything Check to see if obj...

Page 7: ... not cover damages caused by misuse or improper handling installation or maintenance of the product Any return made under this warranty must be accompanied by the items listed below 1 A check in the amount of 15 00 to cover the cost of handling 2 Name and address for product return 3 An explanation of the defect 4 Product should be well packed in a sturdy outside shipping carton to prevent damage ...

Reviews: