How to Troubleshoot a Bushnell 440 X 60 Refractor Telescope

Test the Telescope's Optics

• 1

  Use the telescope during the day to verify that its optics do not need realignment.

• 2

  Aim the telescope at a distant object, such as a telephone pole or tree.

• 3

  Look through the eyepiece. Adjust the focus knob to sharpen the image. If you cannot bring the image into focus, the telescope's optics might need realignment, a process known as collimation. Contact Bushnell for professional collimation.

Align the Finder Scope

• 4

  Check the alignment of the finder scope if you experience difficulty locating targets.

• 5

  Aim the telescope at an astronomical target such as the moon or a bright star. Look through the finder scope and adjust the orientation of the telescope to center the object in the finder scope's field of view.

• 6

  Insert an eyepiece into the telescope focuser and look through it. You should see the object centered in the eyepiece's field of view. If not, adjust the orientation of the telescope to center the object in the eyepiece's field of view.

• 7

  Look through the finder scope. Adjust the two alignment screws on the finder scope to center the object in the field of view. Turn the vertical thumbscrew to raise or lower the object in the field of view, and turn the horizontal thumbscrew to move it left or right.

• 8

  Look through the finder scope and the eyepiece to verify that the object is now centered in both fields of view.

Check the Telescope's Magnification

• 9

  Verify that you aren't exceeding the magnification limits of the telescope. A 60mm telescope typically works best at magnifications below 120x.

• 10

  Divide the focal length of the eyepieces you use by the focal length of the telescope to determine the magnification. For example, a 10mm eyepiece provides 44x magnifying power with the Bushnell 440mm refractor.

• 11

  Do not use eyepieces less than 4mm in focal length with the Bushnell refractor. A 4mm eyepiece provides 110x power with the telescope, whereas a 3mm eyepiece produces nearly 147x magnifying power. Excessive magnification dims the image and makes observing difficult.

• 12

  Use low magnifications, 50x or lower, for large objects such as star clusters and nebulae. Use medium magnifications, between 50x and 100x, when observing globular clusters and galaxies. Rely on high magnifications only when viewing the moon, planets and bright stars.