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The eyepiece (or ocular) is an optical element that magnifies the image focused
by the telescope. Without the eyepiece it would be impossible to use the
telescope visually. Eyepieces are commonly referred to by focal length and
barrel diameter. The longer focal length (i.e., the larger the number) the lower
the eyepiece magnification (i.e., power). Generally, you will use low-to-
moderate power when viewing. For more information on how to determine
power, see the section on “Calculating Magnification”. The eyepiece fits
directly into the focuser of the Newtonian. To attach the eyepieces:
1.
Make sure the thumbscrews are not protruding into the focuser tube.
Then, insert the chrome barrel of the eyepiece into the focus tube (remove
the plug up cap of the focuser first) and tighten the thumbscrews – see
Figure 2-15.
2.
The 20mm eyepiece is called an erecting eyepiece since it corrects the
image so it is right side up and corrected left to right. This makes the
telescope useful for terrestrial viewing.
3.
The eyepieces can be changed by reversing the procedure as described above.
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Your telescope also comes with a 3x Barlow Lens which triples the
magnifying power of each eyepiece. However, the greatly magnified
images should only be used under ideal conditions – see the Calculating
Magnification section of this manual.
Figure 2-16
To use the Barlow lens with refractors, remove the diagonal and insert the Barlow directly into the focuser tube.
You then insert an eyepiece into the Barlow lens for viewing. You can also, insert the diagonal into the Barlow lens
and then use an eyepiece in the diagonal but you may not be able to reach focus with all eyepieces.
For Newtonian telescopes, insert the Barlowlens directly into the focuser. Then, insert an eyepiece into the Barlow
lens.
Note
: Start by using a low power eyepiece as it will be easier to focus.
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The PowerSeeker 50AZ comes with a 1.5x erecting eyepieces, primarily for daytime terrestrial viewing. This
eyepiece corrects the image you see in your telescope, so that it’s both right side up and corrected from left to right.
Install and use this eyepiece the same way you do with the Barlow Lens in the section above. You cannot use the
Barlow lens when using this eyepiece.
When using the erecting eyepiece, the power with various eyepieces is:
w/ 20mm = 45x
w/12mm = 75x
w/ 4mm = 225x
Figure 2-15
